Conference Agenda

Warming oceans affect the growth, reproduction, and location of fish species. Using a bioeconomic framework, we estimate the relationship between sea surface temperature (SST) and the catch of de facto open-access commercial fisheries of flatfish, trevally, and jack mackerel in New Zealand. Assuming either a logarithmic or quadratic relationship between the SST and the carrying capacity of the fish stock, we consider three fishing methods (bottom trawl, set net, and midwater trawl) and two measures of effort (count and duration). We show that ocean warming results in an increase in catch for all species if we assume a logarithmic relationship, with the highest marginal product of SST (〖MP〗_SST) for jack mackerel caught using midwater trawl. The highest marginal revenue product (computed by the MPSST, current price and fished area) is found for flatfish caught by set net. However, when assuming a quadratic relationship, there is a threshold above which catch starts to decrease, with the maximum catch of species ranging between 10 and 12.2 °C. These results also vary spatially, with higher values of MPSST observed in areas closer to the South Pole. Our findings are relevant for any review of fisheries management systems in response to ocean warming.

Natural capital asset pricing methods can describe wealth losses from shifts in the behavior of actors that comprise socio-environmental systems. Many natural capital assets, including marine fisheries, are governed by a set of institutions or actors rather than a single social planner, motivating the need for an asset pricing framework that explicitly accounts for multiple interacting actors operating over a shared resource. We compare the one-actor/one-stock approach to the two-actor case through a simulation exercise and show that actions by one actor can impact another actor’s asset price function for a shared stock. Multi-actor natural capital asset pricing can be an effective framework for considering the impact of climate change on ocean resources, the propensity for conflict over these resources, and potential solutions to the challenge of ocean sustainability.

Seasonality is a fundamental environmental feature of many resource industries, such as fisheries, and growth can be characterized in different ways. Both seasonality and growth are natural processes that are important to understand and model for efficient management. The generalized Gordon-Schaefer model for microdata incorporates impacts from gear and fishing area on productivity and has been promoted with policy relevant implications. We extend this model with seasonal adjustments and alternative growth specifications, and estimate it for the Norwegian cod fishery using trip-level landing data and satellite tracking of vessels. We estimate the model in two stages. First, we estimate a production function that includes season-, area-, gear-, and time-fixed effects. From this stage, we extract an estimate for the stock abundance. In the second stage, we use the stock as dependent variable and estimate some alternative stock growth equations. The estimated stock abundance and the policy benchmark maximum sustainable yield compare well against established stock assessments and related harvest advice. Policy implications vary substantially with growth characteristics, however, suggesting that careful considerations are required for policy relevance.

Overfishing is a global problem. In Europe, 40-70 percent of fish stocks are overexploited. We use statistical analysis to shed light on the policy positions taken by the EU’s member countries in the negotiations on fishing quotas (TACs) and, in turn, whether some countries are driving the exploitation of fish stocks by bargaining for high TACs. We use panel data on TACs and scientific recommendations from ICES for 165 zone-species combinations during 2001-2020. Using fixed-effects models, we estimate the Faroe Islands’, Ireland’s, as well as Portugal’s and Spain’s policy positions to be significantly above the ICES recommendation and those of Germany to be significantly below. Thus, our evidence suggests that Portugal, Spain, and, in particular, the Faroe Islands aim for higher TACs, while Germany seeks to reduce TACs. Our study contributes to a better understanding of the political processes and behind-closed-doors negotiations that determine fishing quotas.