Dolfi Debrot

'Nature-based Solutions': essential to safeguard the Dutch Caribbean against the consequences of climate change

This powerpoint walks through the recently published position paper entitled Nature based Solutions’: essential to safeguard the Dutch Caribbean against the consequences of climate change.

Date
2022
Data type
Research report
Theme
Education and outreach
Research and monitoring
Report number
Position paper powerpoint
Geographic location
Aruba
Bonaire
Curacao
Saba
Saba bank
St. Eustatius
St. Maarten

Update on the 2012-2020 trends in the St. Eustatius fisheries

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.

Date
2021
Data type
Research report
Theme
Research and monitoring
Report number
C059/21
Geographic location
St. Eustatius