See discussions, stats, and author profiles for this publication at: https://www.researchgate.net/publication/271919728 Effects of fishing during the spawning period: implications for sustainable management ARTICLE in REVIEWS IN FISH BIOLOGY AND FISHERIES · MARCH 2014 Impact Factor: 2.73 · DOI: 10.1007/s11160-014-9370-x CITATIONS READS 5 58 2 AUTHORS, INCLUDING: Adriaan D. Rijnsdorp Wageningen UR 240 PUBLICATIONS 6,659 CITATIONS SEE PROFILE All in-text references underlined in blue are linked to publications on ResearchGate, Available from: Adriaan D. Rijnsdorp letting you access and read them immediately. Retrieved on: 28 January 2016 Rev Fish Biol Fisheries DOI 10.1007/s11160-014-9370-x REVIEWS Effects of fishing during the spawning period: implications for sustainable management Harrie¨t M. J. van Overzee • Adriaan D. Rijnsdorp Received: 12 February 2014 / Accepted: 22 August 2014 Ó Springer International Publishing Switzerland 2014 Abstract While fishery closures during the spawn- exploitation of specific spawning components. The ing season are commonplace, direct evidence for their contribution of spawning closures to sustainable benefit is mainly restricted to species forming large fisheries will differ among species and depends on spawning aggregations. This paper analyses the con- the complexity of the spawning system, the level of ditions under which spawning closures could contrib- aggregation during spawning and the vulnerability of ute to sustainable fisheries management by reviewing the spawning habitat. The importance of these closures how fishing during spawning may affect the physiol- depends on the degree of population depletion but ogy, behaviour and ecology of individuals and how does not cease when populations are ‘healthy’ (i.e. no this may influence the dynamics and the genetics of the sign that recruitment is impaired). population. We distinguish between the effects of fishing activities in relation to mortality, disturbance Keywords Spawning closures Á Fish Á Invertebrates Á of spawning activity, and impact on spawning habitat. Reproduction Á Spawning aggregations Á Fisheries Spawning closures may be of benefit it they: (1) reduce the fishing mortality of the large and older spawners; (2) avoid negative effects on spawning habitats; (3) reduce the risk of over-exploitation in species which Introduction form large spawning aggregations; (4) reduce the evolutionary effects on maturation and reproductive There is great concern internationally about the effects investment; and (5) reduce the risk of over- of fisheries on populations of exploited species and the ecosystem in which they live (Coleman and Williams 2002; Jackson et al. 2001; Pauly et al. 2002). Although Electronic supplementary material The online version of this article (doi:10.1007/s11160-014-9370-x) contains supple- the exploitation rate has started to decline in some mentary material, which is available to authorized users. well-studied ecosystems, the majority of the assessed stocks worldwide still require rebuilding (Worm et al. & H. M. J. van Overzee Á A. D. Rijnsdorp ( ) 2009). In addition, fisheries may have an adverse IMARES, Wageningen UR, PO Box 68, 1970 AB Ijmuiden, The Netherlands effect on the ecosystem due to the bycatch of e-mail: [email protected] undersized fish or organisms of no commercial value, by changing or adversely impacting habitats through A. D. Rijnsdorp towed bottom gear, and evolutionary changes (Dayton Aquaculture and Fisheries Group, Wageningen University, PO Box 338, 6700 AH Wageningen, et al. 1995; Jennings and Kaiser 1998; Jørgensen et al. The Netherlands 2007). 123 Rev Fish Biol Fisheries Fisheries management faces the difficult task of the population dynamics and sustainable management developing scenarios for sustainable exploitation are used, such as studying the population dynamics while, at the same time, protecting biodiversity and before and after the establishment of a spawning the livelihood of the fishing communities. Generally, closure (Russell et al. 2012), applying a comparative fisheries management applies a combination of mea- approach across species or populations (Sadovy de sures such as landing quota, effort quota, gear Mitcheson and Erisman 2012), or applying a simula- restrictions, size limits and closed areas or seasons. tion approach (Gru¨ss et al. 2014; Gwinn and Allen The establishment of closed areas has gained support 2010). as contributors to the protection of biodiversity Here we analyse the conditions under which (Agardy 1994). Closed areas may also promote spawning closures could make a contribution to the sustainable exploitation through the protection of sustainable fisheries management of fish and inverte- spawning or nursery areas (Murawski et al. 2000; brate species. We apply a mechanistic approach in Pastoors et al. 2000; Russ and Alcala 1996; Sadovy de which the effect of fishing during the spawning period Mitcheson and Colin 2012). on the physiology, behaviour, population dynamics Fishery closures during the spawning season are and genetics is considered and compared to the effect commonplace. Table 1 presents a selection of spawn- of fishing during the non-spawning period. We ing closures illustrating their wide-spread use in terms distinguish between the primary effect of fishing on of location and species, and the differences in the target species (mortality, disturbance of spawning) objectives. First, spawning closures have been estab- and the secondary effect of fishing on the spawning lished successfully to reduce the fishing mortality in habitat. Thereafter, population biological conse- fisheries targeting large spawning aggregations that quences of fishing during the spawning period are are particularly vulnerable to over-exploitation (Sa- discussed. Finally, implications for management are dovy de Mitcheson et al. 2013) (e.g. reef fish; Table 1, considered by presenting a scoring system to infer the #1–2). A review of spawning closures for spawning vulnerability of species to fisheries during the spawn- aggregating reef fish is presented by Russell et al. ing period and by discussing the ecosystem based (2012). Secondly, spawning closures have been approach. implemented successfully in semelparous or short- living species to allow a sufficient proportion of the spawning stock to be able to shed their eggs before Fishing effects during the spawning period dying (e.g. Southern calamary and Chokka squid; versus the non-spawning period Table 1, #3–4). Thirdly, spawning closures have been put into place to protect spawning populations in order To evaluate the effect of fishing during the spawning to enhance the reproductive output of spawning fish period, we analyse the effect of (1) fishing mortality, and hence improve the number of recruits in the (2) spawning disturbance and (3) impact on spawning exploited stock (e.g. European spiny lobster, Pacific habitat separately. As these factors are not restricted to halibut, cod, herring and haddock; Table 1, #5–10). the spawning period, the effects of fishing during the However, none of the latter studies provide compel- spawning period in comparison to the effect of fishing ling evidence to demonstrate that spawning closures during the non-spawning period are discussed are in fact achieving their stated objectives. (Table 2). Opinions in the scientific community about the usefulness of spawning closures are divided (Horwood Fishing mortality et al. 1998; Russell et al. 2012; Sadovy de Mitcheson and Erisman 2012; Sauer 1995). Although the concept Spawning is generally limited to specific areas and of spawning closures may be appealing as it is easy to times (Cushing 1990). Therefore, fishing during the understand, it is hard to study their effectiveness spawning period may target different components of because it is very difficult, if not impossible, to carry the population than during the non-spawning period. out replicated experiments in real fisheries systems The chance of catching the older (and larger) age (but see (Hamilton et al. 2011)). Therefore, alternative classes may be higher during the spawning period as approaches to study the effect of spawning closures on they gather on the spawning grounds, which are often 123 Rev Fish Biol Fisheries Table 1 Several examples of spawning closures for different exploited species around the world S. Species Area Closure Goal Effectiveness No. 1 Red hind (Epinephelus St. Thomas, U.S Closure fishery during spawning Protection of Increase average length, normalization sex ratio, guttatus) Virgin Islands, Red period (December until end spawning and increased fish abundance all indicated that Hind Bank Marine February, implemented in 1990)1,2 aggregations curtailment of fishing at the spawning locale has Conservation contributed to recovery of red hind around St. District Thomas1 Permanent closure (since 1999)3 Protection of Increase in average density, biomass, spawning spawning density3 aggregations and large area of critical fish habitat 2 Brown-marbled grouper Coral triangle (Papua Two spawning aggregation sites were Sustainable fisheries Densities of E. fuscoguttatus and E. (Epinephelus New Guinea) protected by the establishment of and protection of polyphekadion increased at both MPAs, but not fuscoguttatus), Camouflage community-based MPA in 2004 biodiversity at the site that remained open to fishing4 grouper (Epinephelus polyphekadion) 3 Southern calamary Great Oyster Bay, Two short closures in two-week Protect spawning The closure was successful in providing (Sepioteuthis australis) Tasmania blocks