In a new article Joan B. Company and colleagues at the Institut de
Ciències del Mar (CSIC) in Spain describe a mechanism of interaction
across ecosystems showing how a climate-driven phenomenon originated in
shelf environments controls the biological processes of a deep-sea
living resource.
The progressive depletion of world fisheries is one of the key
socio-economical issues of the forthcoming century. However, amid this
worrying scenario, Company’s study demonstrates how a climate-induced
phenomenon occurring at a decadal time-scale, such as the formation of
dense shelf waters and its subsequent downslope cascading can
repeatedly reverse the general trend of overexploitation of a deep-sea
living resource.
Strong downslope currents associated with intense cascading events
displace the population of the shrimp Aristeus antennatus from the
fishing grounds, producing a temporary fishery collapse. However,
nutritive particles brought by cascading waters to deep regions cause
an enhancement of its recruitment process and an increase of its total
landings during the following years.
These new findings resolve the paradox of a long-overexploited
fishery that has not collapsed after 70 years of intense deep-sea
trawling. The results will have a high socio-economic impact, since
this species is the most valuable deep-sea living resource in the
Mediterranean Sea. Because the cascading of dense water from
continental shelves is a global phenomenon whose effects on biological
processes were not considered in the past, it is hypothesized that its
influence on deep-sea ecosystems and fisheries worldwide should be more
important than previously thought.
In this sense, applying the findings to a global fishery scenario,
shelf water cascading sites identified worldwide could be considered as
regions favorable for deep-sea demersal fisheries, just as the
upwelling zones are considered favorable regions for pelagic fisheries.
This paper is particularly timely, since these new results will be of
special relevance to the current debate on the shift from shelf to
deep-sea fisheries.
*Journal reference: Company JB, Puig P, Sardà F, Palanques A, Latasa
M, et al (2008) Climate Influence on Deep Sea Populations. PLoS ONE
3(1): e1431.doi:10.1371/journal.pone.0001431 http://www.plosone.org/doi/pone.0001431
Public Library of Science. January 2008.
