This report is an update of previously published reports presenting an overview of the trends in St.
Eustatius fisheries based on the fisheries data collected on the island from 2012 to 2020.
The fisheries of St. Eustatius remain mostly conducted by small open boats with outboard engines. The
number of fishing trips carried out by the fleet increased over 2014 peaking in 2015 with an average of
79 trips per months, and subsequently decreased in the following years to reach a minimum average of
25 trips per month in 2019. In 2020, the fishing effort per month increased to an average of 42 trips
per month.

The main activity is a Caribbean spiny lobster (Panuliris argus) fishery using traps, also catching a mix
of reef fish. This fishery is responsible for nearly 70% of the lobster landings on St. Eustatius. The trend
in the annual landings in this fishery broadly follows the trends in the fishing effort, with landings
reaching 30 tonnes in 2015 and since 2017 dropping to values comprising between 7 and 9 tonnes per
year. Landings of lobsters from the trap fishery show a strong seasonality with higher landings during
September-March, and low landings during June-July. The abundance index (derived by modelling the
landings per trip) indicates an overall increase in lobster abundance from 2012 to 2020, with temporary
declines in 2015 and 2018. The average carapace length (CL) shows interannual variations without any
specific trend, but is on average 94.5 mm for females and 102 mm for males. This means that an
average of 42% of the lobsters are landed below the legal size limit (95 mm). This problem is especially
acute for females of which 55% of the landings are of sublegal size. Estimations of F/FMSY proxies based
on the length distribution over time suggest an overexploitation of this stock with values of F/FMSY
between 1.25 and 1.375 for females and 1.125 and 1.25 for males.

The species composition of the bycatch of reef fish in the lobster traps is very diverse, and is dominated
by Acanthuridae (Blue Tang, Doctorfish, Surgeonfish), Ostraciidae (Honeycomb and Scrawled Cowfish),
Serranidae (Coney and Red Hind) and Holocentridae (Squirrelfish). The trends in the reef fish bycatch
in the lobster traps decreased from 2014 with values ranging from 9.9 tonnes in 2015 to 1.5 tonnes in
2019 and 1.6 tonnes in 2020. The biomass index calculated from the landings per trip suggests a
decrease in the combined reef fish stock size from 2014 to 2020. Length frequency data for the main
fish species caught in the lobster traps do not show any notable changes over the period studied. F/FMSY
proxies were estimated for the 7 most landed fish species.

The second most important fishing activities after trap fishing are scuba diving and free diving. Both
activities catch spiny lobster and fish though they both are largely dominated by lobster catches. Scuba
and free diving fleets composition and reporting varied considerably during the time period considered
making it impossible to extract a year effect from a GLM approach. Consequently, this approach was
not considered in this fishery. Scuba divers also conduct a fishery targeting Queen conch (Lobatus
gigas), representing roughly 34% of the trips. Estimates of the annual conch landings are highly
variable, and likely to be fairly uncertain due to the lack of information from logbooks in some years.
The mean length of the conch landed appears to be stable over time, at 24.5 cm and 23.7 cm for females
and males, respectively.

Next to the traps and diving fisheries, different line fisheries are conducted around St. Eustatius. A
handline fishery on reef fish produced landings of between 1.7 and 4.3 tonnes of fish per year in the
period 2014-2017, but with much lower estimates during 2018 and 2019, mainly due to a drop in effort.
In 2020, landings increased to 1.2 tonnes. Large pelagic fish are also caught by trolling, with landings
varying between 0.6 and 2.4 tonnes per year (2014 and 2016 respectively), 2020 landings were
estimated at 1.8 tonnes.

Our main recommendations in terms of both management and research and monitoring are as follows:
- Improve control of and compliance with lobster size-limit regulations.
- Develop a FAD (Fish Aggregation Device) fishery management plan as part of a St. Eustatius fisheries development plan.
- Improve port sampling monitoring and subsampling intensity to cover at least one third of the trips dedicated to each fishing métier.
- Keep collecting data on reef fish species to estimate their status. This can be done best by combining more intensive port sampling with fisheries-independent studies on the distribution
and abundance of these species around St. Eustatius.

Summary

Based on traditional knowledge of the Saban fishermen, a spawning aggregation area (SPAG) for the Red Hind (Epinephelus guttatus) and the Queen Triggerfish (Balistes vetula) has long been known at the northeast end of the Saba Bank, locally known as the Moonfish Bank. SPAG’s are very vulnerable to overfishing because these fish aggregations are predictable in space and time. Both are species of special concern throughout the wider Caribbean, due to overfishing. In 2013 a 5-year seasonal closure was arranged that prohibited fishing the Moonfish Bank from the 1st of December to 28th of February, within which, according to local knowledge, mass spawning takes place. The closure ended in February 2018. In this report we provide a preliminary evaluation of the effect of this 5-year seasonal closure on Red Hind and Queen Triggerfish populations of the Saba Bank based on the monitoring of fishes landed in the Saba Port in those 5 years, throughout the year. For both focal species we examined annual differences in the length-frequency distributions and Landings Per Trip (LPT; number of fish landed per fishing trip) from bycatches in both shallow (~30 m) lobster traps and deep (~100 m) snapper trap fisheries, using port landing data from 2011, which is prior to implementation of the closure measure in 2013, until September 2018.

Our preliminary assessment by means of Generalized Linear Model (GLM) analysis gives no indication of any improvement in LPT or mean size caught for either of the two species examined since the seasonal closure was initiated in 2013. Results even suggest a small but significant decrease in the size of Red Hinds caught as by catch in the lobster pot fishery. This means that, based on the port sampling method used, no significant positive effect on the Red Hind and Queen Triggerfish populations of the 5-year closure can yet be demonstrated. There are many possible explanations for this result, which are presented in the discussion. In particular, there is reason to believe that the current closure area may not be large enough to properly protect the Moonfish Bank SPAG and that there likely are other SPAG’s on the Saba Bank that may also need protection. Therefore, further fisheries-independent research on these and other matters is needed on which basis it may be possible to improve protection so that positive evidence of the effectiveness of the closure may be documented in the future.

Based on fisheries-independent visual diver surveys in the shallow (~ 20m depth) coral reef zone of the Saba Bank edges in 2011, 2013 and 2015, the current population status of our focal species (in that limited habitat zone of the Bank) is as follows: Red Hinds averaged 118.7 ± 53.5 (ind. ha-1 ) with a mean size of about 24 cm, while Queen Triggerfish averaged 56.0 ± 37.6 (ind. ha-1 ) with a median size of about 29 cm (data of 2011, 2013 and 2015 combined). For both focal species, the median size landed in the fishery (Red Hind: about 31 or 33 cm depending on the type of fishery pots; Queen Triggerfish: 34 cm) was considerably larger than the mean size of the population on the reef based on surveys along the available coral reef transects. This is generally to be expected as fishing gears and fisheries typically select for larger individuals. We cautiously suggest that compared to many other areas in the Caribbean (e.g. Bonaire and Curaçao) where the Red Hind and the Queen Triggerfish once were common but now have disappeared, the populations of both these species living in the shallow coral reefs of the Saba Bank still seem relatively healthy in terms of both population density and sizestructure. Based on experiences elsewhere in the region, there is no question that protection of spawning aggregations is a basic need for sustainable management and fishery production in mass-spawning species. Therefore, our main management recommendation is that the closure should continue. However, to reliably asses the effect of seasonal closure and to further improve protection of the spawning grounds for these species, more intensive and consistent data is needed from port sampling which should also (minimally) include data on sex and maturity of the landed fish, even though such data fall outside the typical scope of routine fisheries port sampling. Most critically, directed fisheriesindependent research will be needed to answer several critical questions regarding stock status and Wageningen Marine Research report C040/20 | 5 of 40 when and where spawning aggregations are actually taking place, to improve the effectiveness of seasonal closures of spawning areas of Red Hind and Queen Triggerfish on the Saba Bank.

Referenced in BioNews 38 Article "Protecting Saba Bank’s Red Hind and Queen Triggerfish Populations"