Crop rotations in the sea: Increasing returns and reducing risk of collapse in sea cucumber fisheries

Abstract

Rotational harvesting is one of the oldest management strategies applied to terrestrial and marine natural resources, with crop rotations dating back to the time of the Roman Empire. The efficacy of this strategy for sessile marine species is of considerable interest given that these resources are vital to underpin food security and maintain the social and economic wellbeing of small-scale and commercial fishers globally. We modeled the rotational zone strategy applied to the multispecies sea cucumber fishery in Australia's Great Barrier Reef Marine Park and show a substantial reduction in the risk of localized depletion, higher long-term yields, and improved economic performance. We evaluated the performance of rotation cycles of different length and show an improvement in biological and economic performance with increasing time between harvests up to 6 y. As sea cucumber fisheries throughout the world succumb to overexploitation driven by rising demand, there has been an increasing demand for robust assessments of fishery sustainability and a need to address local depletion concerns. Our results provide motivation for increased use of relatively low-information, low-cost, comanagement rotational harvest approaches in coastal and reef systems globally.T he sustainable management of natural resources is a fundamental challenge in the face of increasing human population and related demand for food, limited research and management capacity, and the drive for short-term economic development. Benthic organisms that are shallow and have limited motility can be particularly susceptible to overharvesting, especially, such as in the case of sea cucumbers, when they are comparatively valuable and easy to harvest and store and where communities rely on these resources for food and income (1, 2). The value and demand for sessile marine resources, such as sea cucumber, are rising (3), resulting in the general overexploitation and even high extinction risk for some sea cucumber populations globally (3, 4), even in seemingly well-managed fisheries, such as in the Great Barrier Reef Marine Park (GBRMP) (5, 6). Globally, there is a need to assess fishery sustainability to meet increasingly stringent requirements for ecological sustainability, particularly in regions with high conservation value. However, gathering and analyzing suitable fishery-dependent and -independent data are often beyond the financial and logistical capacities of the fishery, particularly for multispecies fisheries.In our study, we estimated the benefits of a rotational zone strategy (RZS) applied to the sea cucumber fishery of Australia's Great Barrier Reef (GBR) (Fig. 1), which has a 3-y rotation cycle through 154 zones. Under pressure from management over historical overexploitation of high-value species and a perceived high risk of overexploitation of other species, the fishers of the GBR sea cucumber fishery designed and implemented an RZS in 2004, where the entire GBR fishery area was split into 154 zones, with each zone fished only one time every 3 ...

Demonstrating multiple benefits from periodically harvested fisheries closures

“…To overcome this issue, empirical data could be combined with population modelling to assess the potential of PHCs for long‐term sustainability of fish stocks and conservation (Carvalho et al., ). This would also allow for the assessment of long‐term fisheries benefits and whether effort displacement following PHC implementation may lead to overharvesting in the nearby areas open to fishing, an issue that is currently in debate with rotational fisheries (Game, Bode, McDonald‐Madden, Grantham, & Possingham, ; Kaplan, Hart, & Botsford, ; Plagányi, Skewes, Murphy, Pascual, & Fischer, ; Plagányi et al., ; Purcell, Uthicke, Byrne, & Eriksson, ).…”

Fish wariness is a more sensitive indicator to changes in fishing pressure than abundance, length or biomass

“…Fisheries benefits from temporal or rotational closures through the build-up of abundance and biomass have primarily been demonstrated for sessile or sedentary invertebrates (e.g., Hart 2003, Valderrama and Anderson 2007, Plagányi et al 2015. While such benefits are predicted for reef fish (De Klerk andGatto 1981, Game et al 2009), these have only been demonstrated in a few cases (Cinner et al 2006, Bartlett et al 2009, Jupiter et al 2012.…”

A Holistic Approach to Fishery Management: Evidence and Insights from a Central Mediterranean Case Study (Western Ionian Sea)

“…The alternating fishing ban (Dunn et al, 2011;Rassweiler et al, 2012;Russo et al, 2014b;Plagányi et al, 2015) can be considered a management strategy that, given a feasible control in the harbors-as for the seasonal fishing ban-could efficiently change the exploitation pattern, thereby redirecting the fishing activity toward biggest individuals and making the harvest strategy more viable. Indeed, this alternating fishing ban could produce a less severe impact on landings and revenues than the seasonal fishing ban does, while having almost the same effect on the improvement in the SSB and reducing the proportion of smaller individuals, which are less profitable in the market.…”