Marine reserves aim to protect harvested species within their boundaries and can therefore provide insurance against the effects of overfishing. To evaluate whether marine reserves are meeting this expectation, we compiled over 40 years of rock lobster (Jasus edwardsii) monitoring data and examined long-term trends in three relatively small marine reserves (c.4-8 km 2) in northern New Zealand, a region that has experienced large-scale declines in the fishery over the last decade. In all three reserves, lobster density initially increased by at least a factor of three following protection. However, over the last 10 years, lobster populations have experienced large declines in all three reserves with densities now 59-80%, and spawning stock biomass (SSB) now 51-86%, below historic levels. Using peak lobster density in each reserve as an unfished reference point, current densities on fished reefs are <15% of unfished levels and SSB is currently only 3-12% of peak population biomass in reserves. These results highlight the poor state of the wider stock and declines in the reserves follow regional declines in catch-perunit-effort in the fishery, suggesting that lobster populations within these reserves are not fully protected from fishing. Adult J. edwardsii are known to undertake seasonal foraging excursions that carry them beyond the offshore boundaries of these reserves where they are susceptible to fishing-related mortality. We propose that the observed declines are likely a result of direct harvest of individuals beyond reserve boundaries and that larger reserves which encompass both a species' longshore and offshore movements are needed. K E Y W O R D S fishing the line, Jasus edwardsii, marine protected areas, marine reserve design, offshore movement, spillover 1 | INTRODUCTION Coastal marine ecosystems are critically important habitats that are under increasing pressure due to overfishing,

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Increases in global temperatures are expected to have dramatic effects on the abundance and distribution of species in the coming years. Intertidal organisms, which already experience temperatures at or beyond their thermal limits, provide a model system in which to investigate these effects. We took advantage of a previous study in which experimental plates were deployed in the intertidal zone and passively warmed for 12 years to a daily maximum temperature on average 2.7°C higher than control plots on the adjacent bedrock. We compared the composition of the biological communities on each experimental plate with its neighboring bedrock control. Plate communities showed decreased richness of taxa and percent cover of filamentous algae, mussels and mobile grazers relative to bedrock, and increased percent cover of biofilm. We then used short‐term time‐series measurements of plate and bedrock temperatures and a mechanistic heat‐budget model to hindcast those temperatures back 12 years. Greater differences in long‐term average temperature between the experimental plates and bedrock controls were correlated with lower similarity in community composition. Additionally, years with higher average differences between plate and bedrock temperatures were more predictive of current compositional similarity between plate and bedrock communities, even though they occurred farther in the past than did more recent, but cooler, years. We conclude that current intertidal communities reflect their long‐term, rather than short‐term, thermal histories. Mechanistic heat‐budget models based on short‐term measurements can provide this valuable, long‐term information.

The effect of grazers on the diversity, distribution, and composition of their principal food source has rarely been described for the high intertidal zone of rocky shores, a model system for studying the potential effects of climate change. Along rocky, wave-swept shores in central California, the microphytobenthos (MPB) supports diverse assemblages of limpets and littorine snails, which, at current benign temperatures, could potentially partition food resources in a complementary fashion, thereby enhancing secondary productivity. Two limpet species in particular, Lottia scabra and L. austrodigitalis, may partition components of the MPB, and are likely to affect the composition of the MPB on which they graze. In this study, we describe the composition, nutritional value (C:N ratio), and fluorescence (an index of chlorophyll density) of ungrazed, L. scabragrazed and L. austrodigitalis-grazed MPB, each as a function of temperature. Fluorescence decreased with increased average daily maximum temperature for ungrazed MPB, but temperature had no discernible effects on either fluorescence or the composition of the MPB of grazed assemblages. L. austrodigitalis and L. scabra did not partition the MPB, and did not exhibit complementarity. Both species exhibited an ordered grazing scheme, in which limpets grazed down certain components of the MPB before others, and grazing increased the C:N ratio of the MPB, decreasing its nutritional value. Taken together, these results suggest that L. austrodigitalis and L. scabra may experience increased competition as warming temperatures reduce the available MPB.