Catch Composition and Selectivity of Fishing Gears in a Multi-Species Indonesian Coral Reef Fishery

Abstract

There are millions of small-scale fishers worldwide that rely on coral reefs for their livelihood. Yields from many of these coral reef fisheries, however, have been declining. In Indonesia and other coral reefs worldwide, management approaches are dominated by marine protected areas but other options including gear-restrictions may be feasible and more adaptive to local ecological and social conditions. Yet, there is little data on the impacts and selectivity of fishing gears for coral reef fisheries. In this paper, we present results from a case study on the island of Lombok, where we examine the selectivity and overlap in catch composition of the two main fishing gear types: spearguns and handlines. The catch per unit effort (CPUE) was greater in handlines than spearguns, 10.8 and 9.97 kg trip −1 , respectively. The two gears targeted different fish communities with little overlap in dominant species, suggesting a partitioning of resources; handlines targeted piscivores, whereas spearguns targeted mostly herbivores. Mean trophic level was 3.6 for the handline catch and 2.8 for spearguns, where it was inversely related to CPUE. Spearguns captured more species overall and the number of species increased as the CPUE increased. Length parameters of maturity indicated that neither gear showed signs of (growth) overfishing and fishing grounds dominated by speargun fishers had catches associated with younger ages at first maturity than handlines. Our findings provide local baseline data on the potential utility of gear restrictions as a management tool. Specifically, managers could monitor reefs and reduce handlines when piscivorous fishes are low and on spearguns when species diversity is low or algal abundance is high. Should it become more desirable to implement ecosystem approaches to management that are adaptive to changing ecological and social conditions, these indicators may be used as starting points along with local management preferences of fishers.

Gillnet Selectivity on the Narrow-barred Spanish Mackerel (Scomberomorus commerson) Fishery in Pangandaran Waters

“…Tropical waters have a variety of types of fish resources contained in them. This makes one fishing gear able to catch multispecies and one species can be caught by various fishing gear (multigear) [15]. However, in this study the findings are different since this was a single gear fishery.…”

Spatial subsidies drive sweet spots of tropical marine biomass production

“…These are likely to coincide with the plankton subsidy “sweet spots” we identify as dominating local reef fish biomass production, as reported previously for specific locations (e.g., [ 23 , 34 , 59 , 60 ]). Critically, the planktivorous fishes underscoring this seascape function include both small, often colourful fishes (important prey of targeted reef predators), and medium to large-sized, school-forming reef fishes that may be major components of tropical reef fisheries yields (e.g., fusiliers [Caesioninae], planktivorous surgeonfishes and unicornfishes [Acanthuridae], and baitfish [Clupeidae] [ 34 , 35 , 60 – 63 ]). Furthermore, we found a positive relationship between the productivity of planktivores and of predatory fishes ( S1 Text , S6 Fig ), which constitutes evidence supporting the hypothesis that planktivores may compose a major source of prey for predatory fishes.…”

A Comparison of Traditional and Locally Novel Fishing Gear for the Exploitation of the Invasive Atlantic Blue Crab in the Eastern Adriatic Sea

“…Gear efficiency is the probability of catching a particular fish within the area affected by a given type of fishing gear during a single operation [25]. Gear selectivity in the context of this study is defined as the proportion of crabs caught by each fishing gear type [26,27]. Finally, gear productivity is the CPUE of each type of gear for Blue Crabs (in units, kg/gear/day).…”