The invertebrate community is very important to the overall ecology of the LSJRB. It is also important economically for commercial and recreational fisheries. Commercially harvested invertebrates in the lower basin include blue crabs, bait shrimp, and stone crabs. Of the five counties studied (2007-2022), Duval County generally reported the highest catch of crabs (mean 537,941 lbs. per year; SD = ± 180,301 lbs. per year). Recreational fisheries in the area are probably significant for the species mentioned although the level of significance is unclear since there are few reports on recreational landings.

The blue crab (FWRI 2013a) is a very common benthic predator that inhabits estuarine and nearshore coastal habitats in northeast Florida. They are general feeders (omnivores) that will eat fish, aquatic vegetation, molluscs, crustaceans, and worms (FWRI 2002). In the St. Johns River, they reproduce from March to July and then again from October to December (Tagatz 1965; Tagatz 1968a; Tagatz 1968c). Females carry fertilized eggs and migrate towards the more marine waters near the mouth of the river where they will release their eggs into the water. At this point, the young are called zoea, and they drift and develop along the continental shelf for 30-45 days. Wind and currents eventually transport the larger megalops larvae back to the estuarine parts of the river where they may settle in submerged aquatic vegetation (SAV) that serves as a nursery for them. SAV in the river is not considered to be critical to this species, but the exact mechanism by which megalopea return to estuaries is not fully understood even though research indicates that the many factors that can affect water flow rates influence this return (SJRWMD 2012b). Within 6-20 days of landing at this location, the young will molt and become what is recognizable as a blue crab. In 12-18 months, young crabs will then become sexually mature, ultimately reaching a width of eight inches.

Blue crabs are very important in both the benthic and planktonic food webs in the St. Johns River. They are important predators that can affect the abundance of many macroinvertebrates, such as bivalves, smaller crabs, and worms. They are also important prey for many species. Smaller crabs provide food for drum, spot, croaker, seatrout, and catfish, while sharks and rays eat larger individuals.

A strong recreational blue crab fishery exists, although there are relatively few data on it. The blue crab fishery is the largest commercial fishery in the LSJRB (Figure 3.1). In 2022, blue crabs (hard- and soft-shell crabs) accounted for 83% of commercial fisheries in the river with 1,274,657 lbs. harvested ($3,176,594). Duval County reported the highest number of crab landings (517,265 lbs.; $1,355,734), followed by St. Johns (394,475 lbs.; $1,046,738), Putnam (185,160 lbs; $467,659), Clay (174,635 lbs.; $300,783), and Flagler County (3,119 lbs.; $10,001).

In 2020, it accounted for 85% of commercial fisheries in the river with 1,613,575 lbs. harvested ($3,194,555). St. Johns County reported the highest number of crab landings (670,423 lbs.; $1,302,849), followed by Duval (559,766 lbs.; $1,160,143), Putnam (238,225 lbs.; $509,648), Clay (137,540 lbs.; $203,076), and Flagler County (7,621 lbs.; $18,839).

In 2019, it accounted for 69% of commercial fisheries in the river with 1,352,970 lbs. harvested ($2,468,750) (an increase of 346,809 lbs. from the previous year). In 2019, Duval County reported the highest number of crab landings (520,214 lbs.; $963,257), followed by St. Johns (471,278 lbs.; $873,605), Putnam (296,101 lbs.; $528,113), Clay (63,259 lbs.; $98,338), and Flagler County (2,118 lbs.; $5,437).

In 2018, it accounted for 60% of commercial fisheries in the river with 1,006,161 lbs. harvested ($2,063,174). In 2018, Duval County reported the highest number of crab landings (499,632 lbs.; $864,284), followed by St. Johns (371,662 lbs.; $802,041), Putnam (147,831 lbs.; $335,654), Clay (36,210 lbs.; $59,421), and Flagler County (826 lbs.; $1,774).

In 2017, it accounted for 82% of commercial fisheries in the river with 1,508,962 lbs. harvested ($2,584,383). Duval County reported the highest number of crab landings (562,043 lbs.; $981,151), followed by St. Johns (531,867 lbs.; $855,638), Putnam (288,973 lbs.; $555,133), Clay (117,159 lbs.; $175,716), and Flagler County (8,920 lbs.; $16,745). The fishery was affected by significant storm activity in late 2017 and into 2018, it accounted for 60% of commercial fisheries in the river with 1,006,161 lbs. of blue crabs harvested in 2018 (a drop of 502,801 lbs. from the previous year). These years represent the current norm and breakdown of blue crab landings since 2014. Exceptional years produce higher landings as in 2011/2012 when 2.6 to 2.8 million lbs. of blue crabs were harvested with an estimated value of $3.2 to $3.7 million, respectively (FWRI 2023a). The Blue Crab Effort Management Plan implemented regulatory changes during 2010/2011 to reduce the number of blue crab endorsements in Florida subsequently reducing total landings (Florida Department of State 2009. Blue crab. FAC, rule 68B-45).

Blue crab data were collected from commercial reports (1994 to 2022) of landings made to the state and research (2006-2022) from the FWRI.

The primary limitation with the commercial landing data is that it does not account for young crabs that are too small to be harvested. Additionally, there may be uncertainties regarding the location of where the crabs are collected. Fishermen (crabbers) landings reports are made based on the county that landings are made in, and Crabbers often travel around to different counties depending on the season. In addition, some counties share a single bank of the river, not both, and it is uncertain what part of the river the crabs were caught. Changes in harvesting regulations over the years limit what can be said of landings between certain times. In this report, total landings are graphed. However, in order to best assess comparison of landings over the years, landings per trip are calculated, and trends investigated using Kendall tau analysis. In terms of the FWRI collection methods assessed in this study, the subsequent data are likely to not have caught the complete size range of crabs that exist within the river.

Commercial landings of blue crabs have been variable from 1986 to 2022, with no significant trend in the northern river section, and a decreasing trend in the southern river section (t = -0.399; p = 0.0003; n = 37). Landings increased in 2011/2012 more than over the past decade but decreased again following that. In addition, more landings occur in the southern versus northern section of the river (Appendix 3.3.2.A). However, from 2007 to 2022, there was no significant trend in landings, but landings per trip increased in the whole river (t = 0.65; p = 0.0002; n = 16), and southern section of the river (t = 0.567; p = 0.001; n = 16).

The FWRI dataset shows consistent trends in abundance from 2006 to 2022 (Figure 3.20). There was a decreasing trend in number per set for juveniles caught with seines (t = -0.353; p = 0.02; n = 17); however, there was not significant trend for juveniles caught with trawls. There was no trend in the number per set of mature adult crabs. From trawl catch data, the abundance of juveniles seems to peak in June and is lowest in November (Appendix 3.3.2.B). Blue crabs were sampled from January to December with 23.1 m seines and 6.1 m otter trawls both with a mesh size of 3.2 mm. Carapace Width (CW) size classes used follow the FIM Annual Report (FWRI 2022b). Blue crabs were caught in zones C, D, E, and F. Adult crabs are usually sampled with 183 m haul seines (mesh size 38 mm), but since mature crab numbers were higher in the otter trawls, these data were analyzed instead. In addition, some individuals classified as adults may still have been reproductively immature due to individual variation in growth rates and timing of maturity (Brodie 2016).

The blue crab commercial fishery continues to be the premier invertebrate fishery within the LSJRB. The recreational fishery is also likely to be very large, although there is no information available on it.

While common within the river, there is uncertainty regarding whether blue crabs are being overfished or not in Florida. This uncertainty is because the maximum age of blue crabs in Florida is not known. Maximum age is one component that is used in a stock assessment model. Depending on the value used, it can affect whether the model suggests crabs are overharvested or not (Murphy et al. 2007). Consequently, this piece of information is needed to more accurately assess blue crab stocks in Florida. Since January 1^st, 2020, recreational blue crab fishers (≥16 years of age) are required to complete an online, no cost recreational blue crap trap registration before placing their traps in the water (FWC 2023d). In the St. Johns River, five or fewer traps can be used to recreationally catch blue crabs throughout the year (ten gallons whole per harvester per day) except from January 16^th to 25^th on even years. Crabs can also be caught using dip nets, crab pots, and handlines. Although it is illegal to harvest egg-bearing females, it is not against the law to harvest non-egg bearing females; however, since female crabs are critically important to ensuring the survival of subsequent generations of crabs, releasing them helps the fishery to be more sustainable in the future. While male crabs can reproduce many times, females only mate once when mature and can store sperm for several months before actually spawning eggs. Currently, recreational blue crab fishers (≥16 years of age) will be required to complete an online, no cost recreational blue crab trap registration before placing their traps in the water (FWC 2023d).

The statistical analysis did reveal a significantly decreasing trend in the FWRI data for the young of year crabs since 2006. Commercial catch data indicated a decreasing trend overall (north/south sections of the river combined) and just in the south section of the river where most crabs are harvested. Catch per trip significantly increased in the north, south and whole river (Appendix 3.3.2.A). Taking everything into account, the current STATUS of blue crab is Uncertain, and the TREND is Uncertain.

There are three penaeid shrimp species that exist within the estuaries and nearshore waters of the northeast Florida region. They are the white, pink, and brown shrimp. The white shrimp is the most common species in local waters. All three are omnivorous feeding on worms, amphipods, molluscs, copepods, isopods and organic detritus. White shrimp reproduce during April to October, whereas pink and brown shrimp can spawn year round (FWRI 2007). However, peak spawning for brown shrimp is from February to March and from spring through fall for pink shrimp. All species spawn offshore in deeper waters with larvae developing in the plankton and eventually settling in salt marsh tidal creeks within estuaries. From there, young will develop for approximately 2-3 months. As they get larger, they start to migrate towards the more marine waters of the ocean where they will become sexually mature when they reach lengths between 3-5 inches. While they generally do not live long (a maximum 1.5 years), they may reach maximum lengths of up to seven inches.

Penaeid shrimp are very important in both the benthic and planktonic food webs in the St. Johns. They are important predators that can affect the abundance of many small macroinvertebrates (see list above). They are also important prey for many species. As smaller individuals, such as post-larvae and juveniles, they provide food for sheepshead minnows, insect larvae, killifish, and blue crabs. As adult shrimp, they are preyed on by a number of finfish found within the river.

The LSJR supports both recreational and commercial shrimp fisheries. The recreational fishery is likely to be large although there is relatively little information on it. In contrast, the commercial shrimp fishery in Duval County is one of the largest fisheries in the region with an estimated value of $ 6,597,071 and 2,404,452 lbs. in 2022 (FWRI 2023a). However, most shrimp obtained for human consumption are caught by trawlers offshore (Table 3.1). Commercial trawling in the LSJR represents a much smaller fishery.

Penaeid shrimp data were collected from commercial reports made to the state (1986 to 2022). These comprised of total bait shrimp landings that were generally collected within the river. These data likely include white, brown, and pink shrimp, although their relative proportions are unknown. Data for only white shrimp were also collected and assessed from research (2006-2022) from the FWRI.

The primary limitation with the commercial landing data is that there are uncertainties regarding the location of where shrimp are collected. Shrimp-fisherman-landings reports are made according to the county in which the landings are made, and it is uncertain what part of the river shrimp were caught in. Additionally, changes in harvesting regulations through the years may limit what can be said of landings between certain periods. In this report, total landings are graphed. However, in order to best assess comparison of landings over the years, landings per trip are calculated and trends investigated using Kendall tau analysis. In terms of the FWRI data set, the collection methods assessed in this study may not have caught the complete size range of shrimp that exist within the river.

There was no significant trend for total commercial landings, but landings per trip of bait shrimp was significant in the northern section of the river from 1986 to 2022 (Figure 3.21). However, there have been drastic fluctuations among the years with peak landings occurring in 2004 and 2020. Less fluctuation occurred from 2009 to 2016, however, since a low in 2017 the total landings and catch per trip appears to have increased in the whole river (north and south, t = 0.288; p = 0.005; n = 38). More bait shrimp are reported in the north versus southern sections of the LSJR (2007-2022) (Appendix 3.3.3.A).

The FWRI dataset shows consistent trends in abundance for white shrimp from 2006 to 2022 (Figure 3.22). There was no trend in the number of YOY white shrimp captured per set from seines, or trawls. The highest numbers of small white shrimp were encountered in the river from May to August (Appendix 3.3.3.B). With seines, nearshore abundance was seen in zones C and D, and fewer numbers occurred in E and F. In contrast, with trawls, a high number was seen in all 4 zones (Swanson 2016).

Commercial harvesting of penaeid shrimp for bait is a relatively small fishery in the LSJR. The recreational fishery is probably moderately sized, although there are no available data about it. Generally, penaeid shrimp are very abundant in the region and may be at slight risk of being overfished in the south Atlantic region (see FWRI 2008d for a review). However, the South Atlantic Fishery Management Council, and Gulf of Mexico Fishery Management Council have established fishery management plans for shrimp to try to ensure they are not overharvested (FWRI 2008d). Recreational shrimping regulations include no size limit; however, there is a bag limit of five gallons (heads on) per person each day and a possession limit of no more than five gallons (heads on) per vessel at any time regardless of the number of people onboard. Allowable harvesting methods that comply with the FWC regulations include dip net, cast net, push net, one frame net, or beach sein. The season is closed during April and May in Nassau, Duval, St. Johns, Putnam, Flagler, and Clay Counties (FWC 2023d).

Statistically, there appears to be no trend in young of year shrimp. However, commercial data indicated a decreasing trend overall and high annual variability. Most shrimp are caught in the northern section of the river and this section has a decreasing trend for catch. In addition, the southern section of the river also exhibited a decreasing trend in catch.

Taking everything into account, the current STATUS of shrimp is Uncertain, and the TREND is Uncertain.

The stone crab is a fairly common benthic predator that inhabits hard bottoms (such as oyster reefs) and grass beds in the northeast Florida area. Stone crabs are opportunistic carnivores feeding on oysters, barnacles, snails, clams, etc. In Florida, stone crabs reproduce from April through September (FWRI 2007). It is unclear where stone crabs sexually reproduce, and females will carry eggs for approximately two weeks before the eggs hatch. The larvae will drift in the plankton and settle and metamorphose into juvenile forms of the adult in about four weeks. In approximately two years, the crabs will then become sexually mature and reach a width of 2.5 inches. They may live as long as seven years.

Stone crabs are considered both predators and prey in the estuarine community, although the population is small in the St. Johns River and limited to the area east of the Dames Point Bridge (Russo 2023). As predators, they can affect the abundance of many macroinvertebrates, such as bivalves, smaller crabs, and worms. As larvae in the plankton, they are preyed on by filter-feeding fish, larval fish, and other zooplankton and as adults, they are preyed on by many larger predators in the river.

The stone crab fishery is unique in that the crab is not killed. The claws are removed (it is recommended to only take one claw, so the animal has a better chance of survival), and the animal is returned to its habitat. The recreational stone crab fishery is extremely small and occurs in the ICW. There is relatively little information on it. Commercially, stone crabs are generally harvested as bycatch within the blue crab fishery (Russo 2023). The highest number of claw landings within the river basin likely comes from Duval County. In 2015, Duval County’s total landings of Jumbo, Large, Medium, Small, and Ungraded crab claws was 2,166 lbs. with an estimated value of $6,371. In 2019, it was higher with 1,438 lbs. harvested with an estimated value of $18,307. In 2022, claw landings fell to 663 lbs. with an estimated value of $11,603. Claw landings from other counties of the LSJR most likely come from collections made in the ICW (FWRI 2023a).

Stone crab data were collected from commercial reports of landings made to the State between 1986 and 2019. There were no available recreational landings data.

Commercial landings of stone crabs have been variable despite an increase in the number of deployed traps (FWRI 2002). Peak landings occurred in 1994 (50,331 lbs.) and 1997 (96,152 lbs.) with generally low landings occurring from 1999 (414 lbs.) to 2001 (3,257 lbs.) and then a gradual increase after that with considerable variability, and with peaks during mostly drought years. From 1998 to 2022, landings increased and landings per trip increased in the north but decreased in the south (Figure 3.23 and Appendix 3.3.3.A). Most of the landings were reported by southern counties of the LSJRB and this is most likely to reflect crab claws harvested in the Intracoastal Waterway of these southern counties than in the river itself.

Stone crabs are not currently at risk of being overfished but are probably now at a level of landings that is all that can be harvested under current conditions along the Florida east coast (Muller et al. 2006). To minimize negative impacts from commercial fisherman, the Florida legislature implemented a crab trap reduction program in 2002. Currently, a maximum of five traps may be used, and there is a daily limit of one gallon per person, or two gallons per vessel, of minimum-sized 2 ⅞-inch claws (tip to elbow). The season is closed from May 2^nd to October 14^th. Although it is not against the law to harvest both claws from legal sized crabs, the common practice is to leave one claw intact before returning the crab to the water. As a result, crabs can feed and defend themselves more effectively while re-growing the removed claw (FWC 2023d).

Taking everything into account, the current STATUS of stone crab is Satisfactory, and the TREND is Unchanged.