Temperate marine protected area provides recruitment subsidies to local fisheries

Abstract

The utility of marine protected areas (MPAs) as a means of protecting exploited species and conserving biodiversity within MPA boundaries is supported by strong empirical evidence. However, the potential contribution of MPAs to fished populations beyond their boundaries is still highly controversial; empirical measures are scarce and modelling studies have produced a range of predictions, including both positive and negative effects. Using a combination of genetic parentage and relatedness analysis, we measured larval subsidies to local fisheries replenishment for Australasian snapper (: Sparidae) from a small (5.2 km), well-established, temperate, coastal MPA in northern New Zealand. Adult snapper within the MPA contributed an estimated 10.6% (95% CI: 5.5-18.1%) of newly settled juveniles to surrounding areas (approx. 400 km), with no decreasing trend in contributions up to 40 km away. Biophysical modelling of larval dispersal matched experimental data, showing larvae produced inside the MPA dispersed over a comparable distance. These results demonstrate that temperate MPAs have the potential to provide recruitment subsidies at magnitudes and spatial scales relevant to fisheries management. The validated biophysical model provides a cost-efficient opportunity to generalize these findings to other locations and climate conditions, and potentially informs the design of MPA networks for enhancing fisheries management.

Dispersal of a nearshore marine fish connects marine reserves and adjacent fished areas along an open coast

“…Parent–offspring pairs in this study demonstrate direct connectivity between no‐take reserves from the network of MPAs surrounding the Monterey Peninsula, as well as between these conservation areas and adjacent areas where recreational fishing is allowed. This second phenomenon confirms the “spillover effect” or “recruitment cross‐subsidy” (Le Port et al, ), whereby reproduction within reserves replenishes fished populations, as larvae born inside protected areas disperse. Connectivity of habitat patches at a local scale reinforces the benefit of marine reserve “networks” that conserve characteristic environments, particularly productive, nearshore, temperate rocky reefs.…”

“…Tracking larval dispersal in the ocean is considered one of the great logistical challenges in marine ecology (Pineda, Hare, & Sponaugle, ). Studies that have successfully addressed this challenge have produced intriguing results regarding the prevalence of self‐recruitment (Berumen et al, ; Jones, Planes, & Thorrold, ), connectivity among reefs (Almany et al, ; Christie et al, ) and the effectiveness of marine reserves (Harrison et al, ; Le Port et al, ; Planes, Jones, & Thorrold, ).…”

“…Furthermore, parentage analysis has been used to test assumptions of marine reserve design: specifically, the ability of reserves to increase the number of individuals within the reserve as well as export individuals beyond reserve boundaries, through either spillover or recruitment subsidies (Botsford et al, ; Botsford, Micheli, & Hastings, ; Sale et al, ). Whether reserves enhance populations in fished areas has been a crucial knowledge gap (Sale et al, ), and many studies have attempted to evaluate the extent to which self‐recruitment, spillover or recruitment subsidies occur (Almany et al, ; Berumen et al, ; Christie et al, ; Harrison et al, ; Le Port et al, ).…”

“…Coral reef environments have dominated dispersal research (Almany et al, ; Berumen et al, ; Christie et al, ; Herrera et al, ; Jones et al, ; Planes et al, ; Saenz‐Agudelo, Jones, Thorrold, & Planes, ), while just two studies have directly measured empirical dispersal in temperate marine environments (Le Port et al, ; Schunter et al, ). The most productive temperate marine regions, those in which coastal upwelling drives ecosystem dynamics, such as the Humboldt, Benguela or California Current ecosystems, are understudied in this respect.…”

Increase in Relative Abundance and Size of Snapper Chrysophrys auratus Within Partially-Protected and No-Take Areas in a Temperate Marine Protected Area

“…Given that the no-take areas are providing refuge for larger C. auratus, a species susceptible to reduced population resilience through age-class truncation (Stewart, 2011), these no-take areas could potentially contribute to rebuilding of local populations as the larger fish are more likely to have higher fecundity and quality of eggs (Berkeley et al, 2004;Stewart et al, 2009). In a recent study in New Zealand, it was demonstrated through genetic parentage and relatedness analysis that adult C. auratus within a no-take reserve contributed newly settled juveniles to surrounding areas (Le Port et al, 2017). Whilst the increased abundance and size of C. auratus within the no-take areas could be contributing to other areas of the marine park by way of larval dispersal and newly settled juveniles, the fishery benefit of this is yet to be quantified and warrants further investigation.…”