For one of my courses at Uni, we were asked to choose a scientific paper of our interest and rewrite it to a so-called popular science article. A popular science article should be easy to read for a finishing high school student (6 VWO for my Dutchies). It should be an engaging article, good to feature in magazines like New Scientist or maybe even National Geographic. I enjoyed writing this piece about the effect of fishing gear restrictions on fish stock.
A golden compromise: solely line fishing on coral reefs
By Jouke van der Velden
In marine conservation, the effectiveness of fishery closure on ecosystem recovery is praised. Coral reef species can thrive again within a couple of years of establishing a no-take zone, where all fishing is prohibited. The fishermen, however, are left with empty hands.
Recent research by Campbell et al. (2017) suggests that some fishery targets also respond well to strict limitations in fishing gear.
Between 2006 and 2012 divers surveyed reef fish in 21 globally distributed Marine Protected Areas (MPA’s are geographically defined areas in the ocean designated for conservation) and on several non-protected sites, with different management regimes: 1. Open access, open for all activity; 2. MPA Several types of fishing gear allowed; 3. MPA Hook and line fishing only; 4. MPA No-take areas where all fishing is prohibited; or 5. Remote areas not easily accessible by fishermen. Fish species, abundance, and size were all recorded during 1396 surveys and statistically analysed.
The results show that biomass (total weight of organisms in a given area) of the reef community and of nine fish species increased significantly on no-take sites when compared to open-access sites. The increase of the nine species varied between 46% and 359%. On line-fishing sites, the increase in total biomass was not significant (37,2%) but four fish species did show significant growth (between 48% and 330%). No meaningful increase in biomass was seen in several-fishing-gear areas, and biomass on remote fishing site was much higher than on open-access sites.
Responses of reef fish species to fishery closures (no-take) and hook and line fishing were highly variable, which likely reflects the unpredictable and slow recovery rates of reef fish, making them highly vulnerable to fishing. The different fish are vulnerable to varying fishing methods; from spears, nets, and traps to bottom trawling and even dynamite fishing. Their recovery should be interpreted accordingly (e.g. line-fished species will only respond well to full closure, not to line-fishing allowed MPA’s).
Also, the response of total biomass on line-fishing management cannot be overlooked. Although not significant, an increase of 37,2% contributes to the conclusion that not only strict fishery closures but also line-fishing sites, could benefit reef fish ecosystems.
Fisheries are logically better off with allowed line-fishing than no fishing at all. The lines-only method results in having less bycatch and will give the coral reef community a chance to recover. Additionally, it is easier to implement and enforce a lines-only regime in many tropical countries where fishers rely on fishing for their income.