3.2. Finfish Fishery

3.2.1. General description

The LSJRB supports a fish community of great ecological, commercial and recreational value to the public. Most of the fish sought after are predaceous fish that are important in maintaining community balance in the areas where they occur. Historically, American eels and shad were huge fisheries in the St. Johns, although populations have decreased to such low levels that they are now not the focus of most commercial fisherman (McBride 2000). Currently, the premier commercially harvested estuarine or marine fish in the lower basin are striped mullet, flounder, sheepshead, menhaden, black drum, croaker and whiting. However, American eels, spotted seatrout, and weakfish are also commercially harvested. In freshwater sections of the river, important species commercially harvested include catfish, gar, bluegill/redear sunfish, shad, American eels, and non-native tilapia. Of the five counties studied, Duval County had the overall highest landings (714,344 lbs. in 2014), and the generally most fish species caught per year except for flounder and menhaden mostly caught in St. Johns County (only includes fish caught within the river and ICW). Furthermore, Duval County ranks second largest among Florida counties in seafood harvested, predominantly shrimp caught in off shore coastal waters (DACS 2014).

The St. Johns River supports a diverse recreational fishery in the lower basin. Within the different sections of the river, significant fisheries exist for freshwater, estuarine or saltwater fish. Popular saltwater species sought after are red drum, spotted seatrout, flounder and sheepshead. Premier freshwater species include largemouth bass, blue gill, and catfish. The abundance of some of these fish species in the river has resulted in a number of very high profile fishing tournaments occurring each year – red drum and bass tournaments being among the most popular.

3.2.2. Long-term trends

For many years, humans have benefited from the thriving fish communities that utilize the LSJR. Indeed, a number of the species sought after today, such as spotted seatrout and sheepshead, were commented on by the naturalist William Bartram as far back as the late 1700s. However, despite the importance of river fisheries over the years, only a few studies have rigorously sampled fish populations in the SJR. In response to this need for more information, the FWRI started a monthly fish-sampling program in 2001 that is designed to understand fish population changes with time in estuarine areas of northeast Florida.

The available long-term research suggests that many of the same species present today (~170 species total) were present in the river back in the late 1960s (McLane 1955; Tagatz 1968b; FWRI 2008b). However, it is unclear whether the numbers of individual species have changed during this time period because of different sampling methods used in these studies. Currently, the most numerically dominant species in the lower basin include anchovy, striped mullet, killifish, menhaden, Atlantic croaker, spot, silversides, and silver perch.

A preliminary study by L. McCloud with SJRWMD (McCloud 2010) compared current FWRI fish data with those collected by Tagatz in 1968 (Tagatz 1968b). Her research suggested that at some areas of the river, observed fish communities were 50% different between 1968 and the 2001-2006 time period. She further suggests that the observed differences in fish communities in these areas may have been the result of a transition zone between marine and freshwater moving further upstream. One of the unique aspects of the St. Johns Estuary is the ability of some marine fish to ascend far upstream into freshwater. For instance, stingrays are abundant in a number of freshwater areas in the river. However, most fish are sensitive to their environment, and can move from an area in response to unsuitable changes in important environmental factors such salinity, dissolved oxygen, and temperature.

3.2.3. Red Drum (Sciaenops ocellatus)

red drum
http://myfwc.com/marine/fish/reddrum.jpg

3.2.3.1. General Life History

Red drum (also called puppy drum, channel bass, spottail bass, red bass, and redfish (FWRI 2015c) are predatory fish that are found in the estuarine sections of the St. Johns River. During the fall and winter, they spawn at dusk in coastal waters near passes, inlets and bays. Newly hatched young live in the water column for 20 days before settling to the sea floor bottom, where they will develop into juveniles that live within estuary creeks and rivers. Young fish will become reproductively mature fish at around three years of age and may ultimately live for approximately 40 years (Murphy and Taylor 1990), and reach a maximum length of 45 inches.

3.2.3.2. Significance

Red drum are ecologically important as both a predator and prey in the food web of the St. Johns River. They are bottom feeders that eat crabs, shrimp, worms, and small fish. Their predators include larger fish, birds, and turtles.

A strong recreational fishery exists for red drum. The recreational fishery for red drum is an estuarine and near-shore fishery, targeting small, “puppy drum,” and large trophy fish. Trophy-size fish are caught along the mid- and south coastal barrier islands, while smaller red drum are taken in shallow estuarine waters. Red drum has not been commercially harvested since 1988 to minimize impacts to natural populations.

3.2.3.3. Trend

The FWRI data set shows consistent trends in abundance from 2001 to 2012, then a decreasing trend in adults in the last three years (2013-2015). However, 2015 only includes data from September to December and does not include January of 2016 (Figure 3.4). Kendall tau correlation analyses revealed no temporal trend in number per set for young of the year (t = -0.162; N.S.); adults were negatively correlated over time (t = -0.543; p = 0.024). The Young of the Year (YOY) appear in the river from September to January and become juveniles in approximately one year (Appendix 3.2.3a).

Figure 3.4
Figure 3.4 Number of young of the year and adult red drum caught within the lower basin of the St. Johns River from 2001-2015. The N value indicates the total number of sets completed for the time period (FWRI 2016b). Young of year red drum were sampled over a split year recruitment window from September to January with 21.3 m seins and a mesh size of 3.2 mm. YOY were caught in zones C, D, and E, at shallow depth (≤1.8 m). Legal sized fish were sampled from January through December with 183 m haul seins (mesh size 38 mm). Slot limit fish were caught in zones C and D along shorelines (Figure 3.2 Sampling Zone Map).

3.2.3.4. Current Status and Future Outlook

Red drum represent an important recreational fishery in the LSJR and appear to be safe from overexploitation (Murphy and Munyandorero 2008). There is concern that increased fishing activity in the future may cause decreases in fish numbers through direct loss of fish captured, and mortality of “returned” fish. Consequently, close monitoring of reproduction and abundance in local populations is essential for ensuring the long-term maintenance of red drum in LSJRB. Taking everything into account, the current STATUS of red drum is satisfactory, and the TREND is unchanged.

Recreationally, a maximum of two red drum may be caught per person per day throughout the year. Individual fish must be between 18 and 27 inches in length, and no red drum may be sold for profit (FWC 2017d).

3.2.4. Spotted Seatrout (Cynoscion nebulosus)

 

spotted sea trout
http://www.floridasportfishing.com/magazine/images

3.2.4.1. General Life History

The spotted seatrout is a bottom-dwelling predator that is common in estuarine and shallow coastal habitats in northeast Florida. It is a carnivore that preys on a number of small fish species, such as anchovies, pinfish and menhaden. Reproduction tends to occur during the night within the river from spring through fall with a peak during April through July. The young often form schools of up to 30-50 individuals. Individual fish will become sexually mature in 2-3 years. Their expected lifespan is 8-10 years. They may reach a maximum length of three feet.

3.2.4.2. Significance

Spotted seatrout are very important in both the benthic and planktonic food webs in the St. Johns. As newly hatched young they are planktivores, feeding primarily on copepods within the plankton. As they grow, they shift to larger prey, including shrimp, and eventually a number of smaller fish within the river. A number of predators feed on seatrout, including Atlantic croaker, cormorants, brown pelicans, bottlenose dolphin, and sharks.

There are recreational and commercial spotted seatrout fisheries within the St. Johns River. Recreationally, the fish is the premier game fish in the area for visiting and local anglers. Annual commercial landings for the state of Florida were over 4 million lbs in the 1950s and 1960s, and down to 45,000 lbs in 2006 (Murphy, et al. 2011). Out of this value, the LSJR (and the neighboring ICW) accounts for approximately 5,000 lbs harvested annually. Reductions in landings since the 1950s and 1960 have been in large part due to more stringent fishing regulations.

3.2.4.3. Trend

Commercial landings decreased substantially in the mid-1980s and again in the mid-1990s (Figure 3.5; Appendix 3.2.4a). However, landings have generally remained variable but consistent for the whole river since 1996 (Appendix 3.2.4a). The substantial mid-1990s decrease may be due to the impact of the gill net ban (Murphy, et al. 2011). The FWRI data set shows consistent trends in abundance from 2001 to 2016 (Figure 3.6). Kendall tau correlation analyses revealed no temporal trend in number per set for young of the year (t = -0.048; N.S.), nor adults (t = -0.219; N.S.). However, there was a small peak in the number of young of the year (SL ≤ 100 mm) caught in 2007, and again in 2012. Young of the year appear in the river from May to November and become juveniles within one year (Appendix 3.2.4b).

Figure 3.5
Figure 3.5 Commercial landings (in lbs) of spotted seatrout within the lower basin of the St. Johns River from 1986 to 2015. Note that gill nets were banned in 1995 (FWRI 2016a).
Figure 3.6
Figure 3.6 Number of young of the year and adults of spotted seatrout caught within the lower basin of the St. Johns River from 2001-2015. The N value indicates the total number of sets completed for the time period (FWRI 2016b). Young of year spotted seatrout were sampled during a recruitment window from May to November with 21.3 m seins and a mesh size of 3.2 mm. YOY were caught in zones C, D at shallow depth (≤1.8 m). Reproductively mature fish reside in zone C, but adults representing the legal slot limit of SL 325-434 mm yielded low numbers (n = 110) and were not included in the analysis. Adults SL ≥ 200 mm included in the analysis yielded more numbers (n = 695) were used in the analysis. Adults were sampled from January through December with 183 m haul seines (mesh size 38 mm). These fish were caught in zones C and D along shorelines (Figure 3.2 Sampling Zone Map).

3.2.4.4. Current Status & Future Outlook

The spotted seatrout recreational fishery has grown in the last 15 years, while the commercial fishery has remained somewhat stable. There has been concern that there could be a decrease in landings with time that may be related to: 1) changes in fishing regulations, 2) coastal development, and 3) fishing pressure (Murphy, et al. 2011). Despite this concern, a recent FWRI stock assessment suggests that spotted seatrout are not being overfished within the northeast Florida region (Murphy, et al. 2011). Taking everything into account, the current STATUS of spotted seatrout is satisfactory, and the TREND is unchanged.

Recreationally, spotted seatrout are considered a restricted species (Murphy, et al. 2011). However, they can be caught all months of the year. The legal size range is 15 to 20 inches (slot limit) with a daily limit of six per person, and each person is allowed to keep one fish (included in the daily bag limit) that exceeds the slot limit of 20 inches. The season is open year round (FWC 2016b).

3.2.5. Largemouth Bass (Micropterus salmoides)

largemouth bass
http://www.usbr.gov/…/activities_largemouth_bass.jpg

3.2.5.1. General Life History

Largemouth bass are predatory fish that occupy shallow brackish to freshwater habitats, including upper estuaries, rivers, ponds, and lakes. When young, they are carnivores feeding on zooplankton, insects and crustaceans, including crayfish. As they get older, they feed on a variety of organisms, such as larger fish, crayfish, crabs, frogs, and salamanders. They reproduce from December through May (FWC 2016). The male builds nests in hard-bottom areas along shallow shorelines. The female then lays her eggs in the nest, where they are fertilized as they enter the nest. The male will guard the nest, and later, the young fry. The fry initially swim in tight schools and then disperse when they reach about one inch in size. Largemouth bass may live up to 16 years, growing in excess of 22 inches in length.

3.2.5.2. Significance

Largemouth bass are very important in freshwater benthic food webs in the lower St. Johns River. Their willingness and aggressiveness to feed on any appropriately sized prey is significant in affecting the abundance of many organisms in the same habitat. Recreationally, bass are a popular game fish in the area for visiting and local anglers.

3.2.5.3. Trend

FWRI research in the past 10 years shows fairly similar yearly abundances from 2005 to 2015 (Figure 3.7). Kendall tau correlation analyses revealed no temporal trend in number per set for young of the year (t = -0.05; N.S.) Young of the year appear in the river from April to August and become juveniles within one year (Appendix 3.2.5a). Primary abundances occur in zones F, E, and since sufficient numbers were caught in zone D too, it was included in the analysis. Note that the analysis started in 2005 with the FWC expanded sampling zones. Also, SL ≤ 100 mm was chosen to follow the same cohort through a longer time frame. Gear used targets the small fish, and there is limited data about the adults.

Figure 3.7
Figure 3.7 Number of young of the year largemouth bass caught within the lower basin of the St. Johns River from 2005-2015. The N value indicates the total number of sets completed for the time period (FWRI 2016b). Young of year LMB were sampled during a recruitment window from April to August with 21.3 m seins and a mesh size of 3.2 mm (this gear targets the small fish). YOY were caught in zones D, E, and F at shallow depths ≤1.8 m (Figure 3.2 Sampling Zone Map).

3.2.5.4. Current Status & Future Outlook

There is not enough information to assess the status of the recreational fishery associated with largemouth bass in the lower St. Johns River. However, they are not likely to be overfished in the near future. Bass are commonly raised in hatcheries and stocked in lakes and ponds throughout Florida. Taking everything into account, the current STATUS of Largemouth Bass is uncertain, and the TREND is unchanged.

Recreational fishermen are permitted to take largemouth bass all months of the year. A daily limit of five per person is allowed with minimum size of 14 inches and only one of the five being more than 22 inches (FWC 2017d).

3.2.6. Channel & White Catfish (Ictalurus punctatus & Ameiurus catus)

catfish
http://myfwc.com/…/images/raverart/White-Catfish.jpg

3.2.6.1. General Life History

Channel and white catfish are omnivorous fish that can be found in primarily freshwater rivers, streams, ponds and lakes. During their lifetime, they may feed on insects, crustaceans (including crayfish), mollusks, and fish. They reproduce in the river in the spring and summer months. The male builds nests where the female lays the eggs and fertilization occurs. The male will guard the nest and, later, the young fry. The fry will leave the nest one week after hatching. As they mature, catfish will tend to occupy bottom areas with slow moving currents. Individuals may live 11-14 years.

3.2.6.2. Significance

Both catfish species are very important in benthic food webs in the more freshwater sections of the LSJR. They are abundant, and feed on a wide variety of organisms during their lifetime (DeMort 1990). They are a major component of the freshwater commercial fishery in Florida. There is also a large recreational catfish fishery within the river. Channel catfish are often stocked in ponds and lakes to maintain population numbers.

3.2.6.3. Trend

Commercial landings of catfish decreased substantially in the mid-1990s (Figure 3.8). This mid-1990s decrease may be due to the impact of the Florida gill net ban. Since this time period, landings have been decreasing in the north (landings mostly likely from tributaries in this area) sections of the river (Appendix 3.2.6a).

Figure 3.8
Figure 3.8 Commercial landings (in lbs) of catfish within the lower basin of the St. Johns River from 1986 to 2016.
Note that the gill net ban went into effect in 1995 (FWRI 2017a).

The FWRI data set shows variable but consistent trends in abundance for both the channel and white catfish from 2005 to 2015 (Figures 3.9 and 3.10). Kendall tau correlation analyses revealed negative correlations over this time period for channel catfish in number per set for young of the year, but this was not significant (t = -0.018; p = 0.479; n = 11). However, there did appear to be a decrease in abundance from 2005 before numbers started to become relatively similar (Figure 3.9). While somewhat variable, YOY Channel Catfish appear in the river from September to December and become juveniles in approximately one year (Appendix 3.2.6b). Primary abundances occur in zones E and F. Note that the analysis started in 2005 with the FWC expanded sampling zones. Also, SL ≤ 100 mm was chosen to follow the same cohort through a longer time frame. Gear used targets the small fish and limited data exists about the adults.

Figure 3.9
Figure 3.9 Number of young of the year, channel catfish caught within the lower basin of the St. Johns River from 2005-2015. The N value indicates the total number of sets completed for the time period (FWRI 2016b). Young of year channel catfish were sampled during a recruitment window from September to December with 6.1 m otter trawls that have a cod end with a mesh size of 3.2 mm (this gear targets the small fish). YOY were caught in zones E and F (Figure 3.2 Sampling Zone Map).

In terms of white catfish, there were also no trends observed in number per set for young of the year (t = -0.091; p = 0.349; n = 11). However, the temporal patterns were particularly variable for young of the year with peaks encountered during 2005 and 2008/2009 and 2012. While also fairly variable, young of the year appear in the river in June, recruit more fully from July to October, and become juveniles in approximately one year (Appendix 3.2.6c). Primary abundances occur in zones, E and F. Note that the analysis started in 2005 with the FWC expanded sampling zones. Gear used targets the small fish and limited data exists about the adults.

Figure 3.10
Figure 3.10 Number of young of the year white catfish caught within the lower basin of the St. Johns River from 2005-2015. The N value indicates the total number of sets completed for the time period (FWRI 2016b). Young of year white catfish were sampled during a recruitment window from July to October with 6.1 m otter trawls that have a cod end with a mesh size of 3.2 mm (this gear targets the small fish). YOY were caught in zones D, E, and F (Figure 3.2 Sampling Zone Map).

3.2.6.4. Current Status and Future Outlook

Both species of catfish are generally common in the St. Johns River. The decrease in commercial landings may be more related to changes in fishing regulations over the years, although this is not known for sure. Further, both species of catfish are commonly raised in hatcheries and stocked in lakes and ponds throughout Florida. If future research suggests that their abundance is decreasing to unacceptable levels, areas of the river can be re-stocked. FWC is in the process of implementing freshwater species into its marine trip ticket program to more effectively assess freshwater landings in various parts of Florida. Consequently, the potential exists for overfishing of these species in the future and with the exception of Fish Management Areas, there is a bag limit of 6 fish per person on channel catfish, no bag limit for white catfish (FWC 2017c). Although there seems to be a slight increase in Young Of Year white catfish, this was not statistically significant. There are limited data about adults in general, and the commercial data suggest a decreasing trend in the northern section. Taking everything into account, the current STATUS of freshwater catfish is uncertain, and the TREND is worsening.

3.2.7. Striped Mullet (Mugil cephalus)

striped mullet
http://www.floridafishandhunt.com/…/stripemul.jpg

3.2.7.1. General Life History

Striped mullet (also known as black mullet) are detritivores that have a wide salinity range. They are abundant in freshwater and inshore coastal environments often being found near mud bottoms feeding on algae, and decaying plant material. Mullet migrate offshore to spawn with their resultant larvae eventually drifting back to coastal waters and marsh estuaries. Developing individuals will become sexually mature at three years and live from 4-16 years. Older fish may ultimately reach lengths of up to three feet..

3.2.7.2. Significance

Mullet are considered extremely important in benthic food webs in all sections of the LSJR. They are abundant and significant in the transfer of energy from the detrital matter they feed on to their predators such as birds, seatrout, sharks, and marine mammals. The commercial mullet fishery has been the largest among all fisheries in the St. Johns for many years with over 100,000 lbs. harvested annually. Additionally, mullet are sought after recreationally for their food and bait value.

3.2.7.3. Trend

Commercial landings and landings per trip have been variable since the 1980s but showed an increasing trend for the period 2007-2016 (t = -0.333; p = 0.09; n = 10). (Figure 3.11). This trend was observed in both the northern and southern sections of the river sections (Appendix 3.2.7a). The FWRI data set shows variable yearly abundances from 2006 to 2015 (Figure 3.12). Kendall tau correlation analyses revealed a negative trend in number per set for young of the year, but this was not significant. Young of the year appear in the river from January through April and become juveniles within one year (Appendix 3.2.7b). Primary abundances occur in zones C, D, E and F. There were two observable peaks in recruitment during 2006 and 2010, possibly influenced by drought conditions in those two years. Note that the analysis started in 2006 because there was no FWC expanded sampling in zones E and F in January to April 2005. Gear used targets the small fish and limited data exists about the adults.

Figure 3.11
Figure 3.11 Commercial landings (in lbs) of striped mullet within the lower basin of the St. Johns River from 1986 to 2016 (FWRI 2017a).
Figure 3.12
Figure 3.12 Number of young of the year striped mullet caught within the lower basin of the St. Johns River from 2006-2015. The N value indicates the total number of sets completed for the time period (FWRI 2016b). Young of year striped mullet were sampled during a recruitment window from January to April with 21.3 m seines (mesh size of 3.2 mm) that target the small fish. YOY were caught in zones C, D, E, and F (Figure 3.2 Sampling Zone Map). *Starts in 2006 due to no expansion sampling in Zones E and F in Jan-Apr 2005.

3.2.7.4. Current Status & Future Outlook

Striped mullet in the St. Johns River continue to be important commercially and recreationally. Populations appear to be healthy and sustainable into the foreseeable future along the east coast of Florida (Mahmoudi 2005). Recreational fishing limitations are 50 fish maximum per person per day (includes Striped and Silver mullet). There is a vessel limit of 50 fish (September 1st to January 31st, and 100 fish from February 1st to August 31st). There is no closed season (FWC 2017d). Taking everything into account, the current STATUS of Striped Mullet is satisfactory, and the TREND is improving.

3.2.8. Southern Flounder (Paralichthys lethostigma)

southern flounder
http://www.uvm.edu/~jbartlet/nr260/animal%20life/marine/southernflounder.gif

3.2.8.1. General Life History

The southern flounder is common in and around inshore channels estuaries associated with the St. Johns River. It is a bottom-dwelling predator that feeds on shrimp, crabs, snails, bivalves, and small fish. During the fall and winter, it moves offshore to spawn. Larvae will develop and drift in the plankton while being transported (primarily via wind driven currents) back to estuaries and lagoons, where they will settle and develop into juveniles and then adults. The southern flounder may grow up to 36 inches and live to approximately three years of age.

3.2.8.2. Significance

Flounder are important ecologically, recreationally, and commercially to humans in the lower St. Johns River area. They are abundant and important in maintaining ecological balance in their roles as both predator and prey. They feed on small invertebrates, such as bivalves and snails, and are preyed on by sharks, marine mammals, and birds. The commercial flounder fishery is one of the larger ones in northeast Florida. Flounder are also highly sought after recreationally for their excellent food value.

3.2.8.3. Trend

Commercially, total landings of all flounders have decreased after 1995 (Figure 3.13; Appendix 3.2.8a). Total flounder landings have decreased significantly for the north river section and increase in the southern section of the river (Appendix 3.2.8a). However, the commercial catch per trip increased in the northern section of the river and a decrease in the southern section of the river. The mid-1990s decrease in commercial landings may be due to the impact of the gill net ban. The FWRI data set shows slight increases in young of year fish in 2005 and 2010, otherwise a relatively flat trend in abundance from 2002 to 2015 (Figure 3.14). Kendall tau correlation analyses revealed no temporal trend in number per set for young of the year using two different gear types (Seines: t = 0.078; N.S: Trawls t = -0.078; N.S.) Young of the year appear in the river from February to June and become juveniles within approximately one year (Appendix 3.2.8b). Primary abundances occur in zones C, D, E, and F, with a noticeable peak in recruitment during 2010, reason unknown at this time. Note that the analysis started in 2002 because there was no sampling done from January to April 2001. Both gear types used targeted the small fish, and limited data exists about the adults.

Figure 3.13
Figure 3.13 Commercial landings (in lbs) of southern flounder within the Lower Basin of the St. Johns River from 1986-2016 (FWRI 2017a).
Figure 3.14
Figure 3.14 Number of young of the year southern flounder caught within the lower basin of the St. Johns River from 2002-2015 (two gear types compared). The N value indicates the total number of sets completed for the time period (FWRI 2016b). Young of year southern flounder were sampled during a recruitment window from February to June with 21.3 m seines and 6.1 m otter trawls (mesh size of 3.2 mm) that both target the small fish. YOY were caught in zones C, D, E, and F. (Figure 3.2 Sampling Zone Map).

3.2.8.4. Current Status & Future Outlook

The southern flounder continues to be important recreationally and commercially in the LSJR. They are fairly common in the St. Johns River and appear to have no short-term risk of being overfished along the Florida east coast (FWRI 2008c). However, to help ensure their maintenance, it is important to have a better understanding of the reproductive and life history ecology of populations within the river. Recreationally, flounder can be caught all months of the year. Legal minimum size limit is 12 inches with a daily limit of ten fish per person (FWC 2017d). Taking everything into account, the current STATUS of Southern Flounder is uncertain, and the TREND is uncertain.

3.2.9. Sheepshead (Archosargus probatocephalus)

sheepshead
http://myfwc.com/marine/fish/sheepshead.jpg

3.2.9.1. General Life History

Sheepshead are common nearshore and estuarine fish that are very often associated with pilings, docks and jetties. They have an impressive and strong set of incisor teeth that are used to break apart prey, such as bivalves, crabs and barnacles. Adults will migrate offshore during the spring to spawn. Fertilized eggs will develop into larvae offshore and be carried towards the coast by currents primarily driven by the wind. The larvae will enter the mouths of inlets and settle in shallow grassy areas. Developing individuals may reach a maximum length of 3 feet.

3.2.9.2. Significance

Sheepshead are ecologically, recreationally, and commercially important in northeast Florida. They are important in maintaining the estuarine and coastal food web as both a predator and prey. They feed on bottom dwelling invertebrates (i.e., bivalves and barnacles) and are fed on by larger predators such as sharks and marine mammals. The commercial fishery is one of the larger ones within the river. Recreationally, sheepshead are valued by fisherman in the area for their high food value.

3.2.9.3. Trend

Commercial landings seemed stable from 1997 to 2003, then declined until 2008. Since 2008, the trend has been increasing but remains below 2003 levels (Figure 3.15). Total landings over time showed a declining trend, as did landings per trip in both north and south sections of the river (Appendix 3.2.9a). It should be noted that data from the southern counties most likely includes a significant number of fish caught in the ICW.

Figure 3.15
Figure 3.15 Commercial landings (in lbs) of sheepshead within the lower basin of the St. Johns River from 1986 to 2016 (FWRI 2017a).

The FWRI data set shows no upward or downward trends in abundance from 2001 to 2015 for harvestable fish (t = -0.055; NS) (Figure 3.16). Kendall tau correlation analyses revealed that there was a negative trend in number per sets for pre-fishery fish (t = -0.448; p = 0.01; n = 15). Young of the year appear in the river in May and become juveniles within approximately one year. Unfortunately, it was not possible to analyze young of year fish due to low numbers (SL ≤ 130 mm) not being well represented in the sampling (Appendix 3.2.9b). These fish reach 1 year of age at 130 mm SL and are fully recruited to the fishery at 268 mm SL. As a result, size classes were chosen based on the FIM Annual Reports (FWRI 2016a) that include pre-fishery 131-267 mm SL and legally harvestable fish SL ≥ 268 mm.

Figure 3.16
Figure 3.16 Number of pre-fishery and harvestable sheepshead caught within the lower basin of the St. Johns River from 2001-2015. The N value indicates the total number of sets completed for the time period (FWRI 2016b). Sheepshead were sampled during a recruitment window from January to December with 183 m haul seines (mesh size of 38 mm) that target the larger fish. Pre-fishery and harvestable sheepshead were caught in zones C and D (Figure 3.2 Sampling Zone Map).

3.2.9.4. Current Status & Future Outlook

Sheepshead continue to be important to both recreational fishermen and commercial fisheries. They are common in the St. Johns River and appear abundant enough along the Florida east coast to maintain populations with current levels of harvest (Munyandorero, et al. 2006). They can be caught all months of the year. Legal minimum size limit is 12 inches with a daily limit of fifteen fish per person (FWC 2017d). Taking everything into account, the current STATUS of Sheepshead is satisfactory, and the TREND is unchanged.

3.2.10. Atlantic Croaker (Micropogonias undulatus)

atlantic croaker
http://www.floridafishandhunt.com/…/atlcroaker.jpg

3.2.10.1. General Life History

The Atlantic croaker is a bottom-dwelling predator that is commonly encountered around rocks and pilings in estuarine habitats. They are named for the croaking sound they make which is accomplished by scraping muscles against their swim bladder. They use their barbels to sense prey, such as large invertebrates and fish. Adults will migrate offshore during winter and spring to spawn. Their offspring will develop in the plankton and be transported back inshore, where they will settle in vegetated shallow marsh areas. They grow rapidly and may attain a maximum length of 20 inches.

3.2.10.2. Significance

Croakers are important to the LSJR in a number of ways. They are very abundant and consequently extremely important in the food web as both predator and particularly as prey. They feed on small invertebrates, and are fed on by red drum, seatrout, and sharks. For many years, their commercial fishery has been one of the biggest in the LSJR. Additionally, they are recreationally caught for their food value.

3.2.10.3. Trends

Commercially, total landings from 1986-2016 have increased for the northern section of the river and whole river (t = 0.389; p = 0.001; n = 31); however, most of the rebound has occurred from 2007 to 2016 (Figure 3.17; Appendix 3.2.10a). Catch per trip also had an increasing trend for the north, south and whole river, but this was not statistically significant. In both sets of commercial data, landings are lower in the southern sections of the river (Appendix 3.2.10a).

Figure 3.17
Figure 3.17 Commercial landings (in lbs) of Atlantic croaker within the lower basin of the St. Johns River from 1994 to 2016 (FWRI 2017a).

The FWRI data set shows consistent trends in abundance from 2001 to 2015 (Figure 3.18). Kendall tau correlation analyses revealed no temporal trend in number per set for young of the year (t = 0.275; N.S.). Young of the year appear in the river over a split year from October to April and become juveniles in approximately one year (Appendix 3.2.10b). Generally, smaller Atlantic croaker have been observed in more freshwater areas of the river and appear to move to more estuarine areas as they get larger (Brodie 2009).

Figure 3.18
Figure 3.18 Number of young of the year Atlantic croaker caught within the lower basin of the St. Johns River from 2001-2015. The N value indicates the total number of sets completed for the time period (FWRI 2016b). Young of year red drum were sampled over a split year recruitment window from October to April with 6.1 m otter trawls (cod end mesh size of 3.2 mm). Note that 2015 includes October to December but not Jan-April 2016. YOY were caught in zones C, D, E, and F. (Figure 3.2 Sampling Zone Map).

3.2.11. Baitfish

baitfish
http://floridasportfishing.com/magazine/baifish

3.2.11.1. General Life History

Baitfish encompass the multitude of small schooling fish that are the most abundant fishes in the lower St. Johns River. There are at least two-dozen species of baitfish in Florida, including anchovies, menhaden, herring, killifish, sheepshead minnows, and sardines. Many of the baitfish species, such as Spanish sardines and thread herring, are planktivores. However, many may also eat small animals, such as crabs, worms, shrimp and fish.

There is high diversity in life history patterns among baitfish species in the LSJR. However, most migrate seasonally either along the coast and/or away from shore. Many become sexually mature at about one year, reproducing by spawning externally at either the mouth of estuaries (menhaden) or offshore (sardines, anchovy). In both cases, larvae hatch out and are carried by currents to estuaries, where the young will eventually join large schools of juvenile and adult fish. In most cases, individuals do not live longer than four years.

3.2.11.2. Significance

Baitfish are very important to the LSJR because they are extremely important in the food web as prey for a number of larger fish species. They are also important as omnivores that recycle plant and/or animal material that is then available for higher trophic levels. Baitfish are commercially and recreationally utilized for their bait value. Recreational use includes bait for fishing, whereas commercial uses may include products, such as fertilizers, fishmeal, oil, and pet food. The primary fisheries in this group are focused on anchovy, menhaden, sardines, and herring (FWC 2000). However, smaller fisheries catch killifish, sheepshead, minnows, and sardines.

3.2.11.3. Trends

Commercial landings decreased in the mid-1990s and have been sporadic since (Figure 3.19; Appendix 3.2.11). The decrease during the mid-1990s may have been due to the Florida gill net ban. While landings of baitfish have remained temporally consistent, the catch per landing showed significant decreasing trends for the north section of the river (t = -0.273; p = 0.034; n = 31), but was not significant for the south river section (t = 0.123; N.S.). Further, baitfish landings seem to be higher in the southern sections of the river. More recently, from 2007 to 2016, catch per trip showed significant increasing trend for the whole river (t = 0.422; p = 0.045; n = 10).

Figure 3.19
Figure 3.19 Commercial landings (in lbs) of baitfish within the lower basin of the St. Johns River from 1986 to 2016 (FWRI 2017a).

3.2.11.4. Current Status & Future Outlook

Baitfish are very abundant in the LSJR and continue to be important commercially and recreationally. They are likely to be sustainable into the foreseeable future. However, researchers at the Fish and Wildlife Research Institute (FWRI) currently are monitoring and assessing the effects of their fisheries management efforts. Recreationally, they can be caught all months of the year. There is no legal size limit (FWC 2017d). Taking everything into account, the current STATUS of baitfish is satisfactory, and the TREND is unchanged.

Water Quality, Fisheries, Aquatic Life, & Contaminants