SignificanceMeeting human needs while sustaining ecosystems and the benefits they provide is a global challenge. Coastal marine systems present a particularly important case, given that >50% of the world’s population lives within 100 km of the coast and fisheries are the primary source of protein for >1 billion people worldwide. Our integrative analysis here yields an understanding of the sustainability of coupled social-ecological systems that is quite distinct from that provided by either the biophysical or the social sciences alone and that illustrates the feasibility and value of operationalizing the social-ecological systems framework for comparative analyses of coupled systems, particularly in data-poor and developing nation settings.

Erisman, B. E., Paredes, G. A., Plomozo-Lugo, T., Cota-Nieto, J. J., Hastings, P. A., and Aburto-Oropeza, O. 2011. Spatial structure of commercial marine fisheries in Northwest Mexico. – ICES Journal of Marine Science, 68: . The spatial structure of commercial marine fisheries in Northwest (NW) Mexico was investigated using official landings data from 39 local fisheries offices in the region. Multivariate analyses revealed a clear spatial pattern in fishing activities, in which there was a positive linear relationship between the species composition of fisheries offices and both latitude and longitude. Fisheries offices formed eight distinct clusters organized by similarities in geographic location, species-group composition, and coastal habitat type. Five of the eight clusters comprised offices from the same geographic region and coastal ecosystem, and the other three clusters contained the largest industrial fishing ports in NW Mexico. The results of this study suggest that NW Mexico would benefit from an ecosystem-based management framework that focuses on the direct, spatial connection that exists between coastal habitats, harvested species groups, and fishing activities within each region. Subdivision into five separate regions is proposed, with management attention paid specially to the few industrialized ports whose fishing capacities and geographic ranges of fishing far exceed the other areas.

Sound produced by fish spawning aggregations (FSAs) permits the use of passive acoustic methods to identify the timing and location of spawning. However, difficulties in relating sound levels to abundance have impeded the use of passive acoustics to conduct quantitative assessments of biomass. Here we show that models of measured fish sound production versus independently measured fish density can be generated to estimate abundance and biomass from sound levels at FSAs. We compared sound levels produced by spawning Gulf Corvina (Cynoscion othonopterus) with simultaneous measurements of density from active acoustic surveys in the Colorado River Delta, Mexico. During the formation of FSAs, we estimated peak abundance at 1.53 to 1.55 million fish, which equated to a biomass of 2,133 to 2,145 metric tons. Sound levels ranged from 0.02 to 12,738 Pa2, with larger measurements observed on outgoing tides. The relationship between sound levels and densities was variable across the duration of surveys but stabilized during the peak spawning period after high tide to produce a linear relationship. Our results support the use of active acoustic methods to estimate density, abundance, and biomass of fish at FSAs; using appropriately scaled empirical relationships, sound levels can be used to infer these estimates.

The reproductive and acoustic behaviours of Gulf grouper Mycteroperca jordani were studied at a spawning aggregation site in the southern Gulf of California, México. In May 2015–2017, divers located and surveyed a spawning aggregation site within Cabo Pulmo National Park. Adult M. jordani conformed to a lek mating system in which large males formed territories over sand adjacent to a rocky reef that were spatially segregated from smaller females outside of courtship and spawning periods. Females moved into male territories during evening hours to spawn. Male courtship behaviours targeted a single female, included head shakes and burst rises and preceded pair spawning prior to sunset. Males and females displayed three shared colour phases, but four phases were sex‐specific. During evening hours, courtship and spawning, both sexes exhibited sexual dichromatism concurrent with reproductive behaviours. The pair‐spawning mating system and observations of bimodal size distributions by sex support previous claims of protogyny in the species. Males produced sounds during territorial patrols, courtship and spawning rushes, which corroborated the importance of acoustic communication within the behavioural repertoire associated with spawning. Long‐term acoustic monitoring revealed increases in total sounds detected day−1 from March through June with diel increases (e.g., evenings) that may be indicative of the spawning season. Observations of spawning on 12 consecutive evenings in May 2017 coupled with extended periods of sound production suggest that spawning does not follow a lunar rhythm. This first description of the mating system and sounds of the endangered M. jordani facilitates future development of seasonal and areal protections to restore and manage the species.

No abstract