Mangrove Fisheries Project: Sinaloa, Mexico

Project Partners
Project Background
March 2012 Trip Report
Broader Proposal – USAID Concept Paper

Project Partners

In this mangrove fisheries project, EcoWB ESPs Dr. Eric Knudsen and Cleve Steward are collaborating in fisheries and mangrove research by providing consultation on experimental design, fish marking techniques, and assistance in field work, as well as preparing proposals for additional funding. This is a collaboration with Drs. Felipe Amezcua Martinez and Francisco Verdugo Flores, and their students, of Universidad Nacional Autonoma de Mexico, Instituto Ciencias del Mar y Limnologia, in Mazatlan, Sinaloa State, Mexico. Northwest Marine Technology has also contributed fish tagging materials and consultation.

Project Background

Importance of estuarine and coastal lagoon systems with mangrove forests in the life cycle of demersal fishes in the southern Gulf of California have always been regarded as high productive zones that serve as an intermediate nursery habitat that may increase the survivorship of young fish. It has been proved that, in the Caribbean, mangroves strongly influence the community structure of fish on neighboring coral reefs, and it has been observed that the biomass of several commercially important species is more than doubled when adult habitat is connected to mangroves. In the Gulf of California, some studies suggest that fisheries landings are positively related to the local abundance of mangroves and, in particular, to the productive area in the mangrove–water fringe that is used as nursery and/or feeding grounds by many commercial species. These studies estimated that the mangrove-related fish and crab species account for 32% of the small-scale fisheries landings in the region. However, the studies undertaken in the Gulf of California are based on the perception of fishermen. No real data obtained from sampling surveys has been analyzed in this region.

Other studies have argued that the function that has always been assigned to the mangroves can also be accomplished by other coastal areas, coastal lagoons, estuaries and estuarine systems without mangrove forests. The problem is that the importance that all these habitats have on the life cycle of demersal fish species, including those of economic importance, has rarely been assessed.

In this sense, the main objective of this study is to determine the role and the importance that mangrove systems have in the life cycle of demersal fish in the southern Gulf of California, which is a site where an extensive small-boat artisanl fishing fleet operates in these kind of systems. The working hypothesis is that the diversity, abundance, and biomass of fish, and therefore fishing production, is higher in marine areas closer to mangrove systems, than in sites where the mangrove is absent. To test this hypothesis, three different estuarine systems are being surveyed. One has a heavily impacted mangrove forest, where the mangrove is mostly absent. Another zone has mangrove but is next to an urban development, and therefore with anthropogenic impacts. The third site has a healthy mangrove forest. The expected results are that the production of fish will be higher in marine areas closer to the healthy mangrove forests. An alternate result would be that the fish species do not require the mangrove forests to complete their life cycle, and coastal areas can function as well as nursery areas, as well as zones of growth, refuge and feeding. In this case the production would not be related to the presence or absence of mangrove forests in the vicinity. This study is important because current rates of mangrove deforestation are likely to have severe deleterious consequences for the ecosystem function and fisheries productivity. If the mangrove forests are as important as they are consider to be, conservation efforts should protect these systems.

March 2012 Trip Report

Eric Knudsen travelled March 5–16, 2012  to the Instituto Ciencias del Mar y Limnologia, in Mazatlan, Sinaloa, MX. Activities included:

  • Coordinating a grant from Northwest Marine Technology for donated marking supplies.
  • Reviewing the study plan and providing consultation with Dr. Amezcua.
  • Establishing the fish marking procedures and training the project team on the techniques.
  • Testing the fish marking techniques on live, captive fish representing primary species to be marked in the field study (100% survival over the first three days).
  • Participating in field work to refine field techniques and mark fish in one of six paired estuary and nearshore ocean fish marking zones (to monitor the movement of fish between zones).
  • Delivering a seminar on EcoWB to the Instituto faculty and students.
  • Reviewing several manuscripts previously produced from the scientists and graduate students.
  • Reviewing a large data set for potential analysis of additional hypotheses.
  • Visiting nearby land owned by UNAM that is slated for development of an experimental mangrove and fisheries research mesocosm.
  • Strategizing on proposed expanded studies of the connections between mangroves and fisheries production and related restoration of mangrove forests.
  • Visiting a local resort to research and negotiate plans for the 2014 Western Division AFS Annual Meeting.

Broader Proposal – USAID Concept Paper

EcoWB is partnering with the Sustainable Fisheries Foundation, UNAM Instituto de Ciencias del Mary Limnologia, Plan Vivo, and the Mangrove Action Project in a proposal to advance research on the role of mangroves in fisheries production, strategies for restoring depleted mangroves, and a program to acquire carbon credits by planting mangroves. Read the concept paper here: Pre-proposal to USAID from SFF and EcoWB to restore mangroves and fisheries in Mexico – short version