Interdisciplinary effort to help endangered species in the Upper Gulf of California, México | POGO

Interdisciplinary effort to help endangered species in the Upper Gulf of California, México

Dr. Rafael Ramírez Mendoza, Physical Oceanography Department at Centro de Investigación científica y Educación Superior de Ensenada (CICESE)

 

The Upper Gulf of California (UGC), a highly productive area, does not seem to have benefited two of its native species: totoaba (Totoaba macdonaldi) and vaquita marina (Phocoena sinus), both of them listed as endangered. In response to the waning of the population of the vaquita marina for the last three years, the Mexican Government has launched a campaign to protect the UGC environment. This initiative calls for the participation of different institutions that have been working on characterizing the UGC to gain a better understanding of its processes. 

 

The Mexican Navy lead the efforts of such institutions as “Universidad Autónoma de Baja California (UABC)”; “Instituto Politécnico Nacional (IPN)”; and “Centro de Investigación Científica y Educación Superior de Ensenada (CICESE)”. The UGC has been the scenario of two oceanographic campaigns, the first in July 2016 and the second in February 2017. Both campaigns aimed at characterizing seasonal variabilities. Both consisted of a grid of fixed stations sampled by the Research Vessel “Río Tecolutla” (former “Knorr”) whereas shallow stations were sampled by means of a small boat. A subgrid covering the specific area where the vaquita marina has been sighted was also sampled. A 72 h time series at the centre of this area was included in the study. Some of the variables measured are temperature, salinity, density, pH, oxygen, fluorescence, turbidity and chlorophyll. Zooplankton and phytoplankton population samples were also taken.

 

CICESE has focused on studying the UGC's hydrodynamics, sediments, benthos population and their relationships. Two current meters were deployed on each campaign at fixed sites and the results are being used to calibrate a numerical model. Although sediments are related to productivity, little is known about sediment dynamics in the UGC, which incidentally presents a mixture of fine and coarse sediments. In order to understand these important processes, recent samples from the seabed were collected and suspended particles were measured in-situ with a particle analyzer which uses laser technology. Preliminary results have confirmed that fine particles present in the area cause flocculation to occur, making the study of sediment dynamics more complex (Fig. 1).

 

Even though some results have already been obtained, the entire data set from the two campaigns and from the different participants is still being analyzed.

 

Figure 1. The particle size analyzer LISST (Laser In-Situ Scattering and Transmissometry) ready for profiling. The particle size increased with the tidal phase from strong currents (upper left panel) to weak currents (lower left panel) in the water column indicating sediment flocculation. Image Credit: Captain Nidia Angulo, Mexican Navy.

  

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