Udate on the 2012-2018 trends in the St.Eustatius fisheries
This report presents an overview of the trends in St Eustatius fisheries based on the fisheries data collected on the island during 2012-2018. The fishery on St Eustatius remains mostly conducted by small open boasts with outboard engines. The number of fishing trips carried out by the fleet increased over 2014 peaking in 2015 with roughly 100 trips per months, and subsequently decreased in the following years to an average of 25 trips per month in 2018.
The main activity is a lobster 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 decreasing to 11 tonnes in 2018. Landings of lobsters from the trap fishery show a strong seasonality with higher landings from September to March, and low landings during June-July. The abundance index (derived by modelling the landings per trip) indicates an overall increase in abundance from 2012 to 2017, and an apparent decrease in lobster abundance in 2018. The average carapace length (CL) shows interannual variations without any specific trend, but is on average 95 mm for females and 102.5 for males. This means that an average of 41% of the lobsters are landed below the legal size limit (95 mm). This problem is especially acute for females of which 56% of the landings are of sublegal size.
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) and Serranidae (Coney and Red Hind). The trends in the reef fish bycatch in the lobster traps also followed the trend in effort, with values ranging from 2.5 to 9.9 tonnes caught per year. The biomass index calculated from the catch per trip suggests a decrease in fish abundance between 2014 and 2016 and a small increase thereafter. Length frequency data for the main fish species caught in the lobster traps do not show any notable changes over the period studied.
The second most important fishing activities after trap fishing are scuba diving and free diving. Both activities catch lobster and fish, but while lobster and fish (mainly coney, red hind and lionfish) are in equal proportion in the landings from scuba diving, landings from free diving are largely dominated by lobsters. The lobster abundance index calculated from the catches per trip in free and scuba diving shows an increase from 2012 to 2016, and a sharp decrease thereafter. This is overall the same pattern as seen in trap-caught lobsters. The difference with the trend in the abundance index calculated based on trap data might be explained by spatial and depth differences in the distribution of the fishing effort between those fisheries. Scuba divers also conduct a fishery targeted on conch, representing roughly 40% of the trips. Estimates of the annual conch landings are very 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 on St Eustatius. A handline fishery on reef fish produced landings between 1.4 and 4.9 tonnes per year in the period 2014-2017, but with much lower estimates in 2018, mainly due to a drop in effort for this year. Large pelagic fish are also caught by trolling, with landings varying between 0.5 and 2.3 tonnes per year.
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 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 metiér.
- Conduct a closer study on both the Coney and the Red Hind. Do this by combining more intensive port sampling and fisheries independent studies on the distribution and abundance of these species around St. Eustatius.