Mangroves as Fish Habitat

<em>Abstract</em>.—To measure secondary productivity of mangrove systems, we estimated the abundance (individuals/m²) and mass increment (g/month) of the two bivalve species: the black ark <em>Anadara tuberculosa </em>and palmate oyster <em>Saccostrea palmula</em>. Mass increments were based on individual growth rates derived from length-frequency distributions analyses. Samples were collected at three mangrove estuaries in a sand barrier at Ensenada de La Paz from August 2007 to July 2009. The average abundance was 1.27 individuals/m² for black ark and 510 individuals/m² for palmate oysters. Estimated growth rates were 3.67 g/month for black ark and 0.18 g/month for palmate oysters. The average secondary productivity of the black ark was 4.51 g•m^-2•month^-1 and peaked during the spring, while for the palmate oyster <em>Saccostrea palmula </em>it was 97.9 g•m^-2•month^-1, with peak productivity recorded during the summer. The findings of this investigation constitute a necessary element for establishing a baseline to evaluate the consequences of the various natural and anthropogenic pressures that the mangrove systems of El Mogote of La Paz Bay, Baja California Sur, Mexico.

Mangroves as Fish Habitat

Scientists have long sought to understand the contribution of mangrove forests to offshore systems, especially the movement of fishes from vegetated shallows to coral reefs (Parrish 1989). Typically, it is on coral reefs that fishing pressure is most intense (Stallings 2009). Previous studies focusing on mangrove-utilizing Caribbean fishes that migrate offshore with ontogeny have been restricted in spatiotemporal extent (e.g., Nagelkerken et al. 2002), and methodological and other differences among these research efforts have hindered quantitative, interstudy comparisons. Moreover, these studies did not directly account for (i.e., incorporate in their data analyses) the potentially confounding influence of human activity (i.e., fishing and/ or habitat degradation) when examining for relationships linking mangrove presence or area to fish abundance on reefs. As a result, it remains unclear whether island-scale observations consistent with mangrove-mediated augmentation of fishes on coral reefs are also evident at the scale of the greater Caribbean region. Human influence on large, high–trophic level Caribbean fishes appears strong (Stallings 2009); therefore, it is important to account for this influence when examining for a mangrove-driven fish subsidy effect at the regional scale.

Mangroves as Fish Habitat

<em>Abstract</em>.—Mangroves are widely understood to be important habitats for fisheries, supporting resident fish, crustacean, and mollusk populations as well as acting as nursery grounds for species that are targeted by offshore fisheries. There is, however, a lack of quantitative data on fisheries that operate in and around mangroves. We carried out a systematic search to gather data on mangrove fisheries from the scientific literature. We filtered the 4,358 studies returned by the search based on their title and abstract and extracted data from 169 of these. Despite the abundance of literature on mangrove fisheries, we were unable to build a data set of comparable, quantitative data of sufficient size to support numerical modeling approaches. In part, this is due to the variety of mangrove fisheries, which range from small-scale subsistence fishing for mollusks and crabs to large-scale industrialized prawn trawling. This is compounded by the broad range of reporting methods and metrics encountered in the literature. We make a number of recommendations to guide the future reporting of mangrove fisheries to allow for better quantification and comparison of fisheries values at large spatial scales.