Mangrove Fisheries Restoration

Coastal mangrove forests of Sinaloa and Nayarit, Mexico are highly productive ecosystems that not only serve as important carbon sinks but also provide a myriad of other critical ecosystem services, including nursery and spawning areas for commercially valuable fish species. The mangrove forests also support a diverse assemblage of other plant and animal species, including 350 species of birds and 40 species of endemic fauna (invertebrates, fish, reptile, amphibians, birds, and mammals). It is an important wintering region for migratory birds. Local residents rely upon mangroves for sustenance and livelihood from commercial fisheries. When mangroves are restored, there will be more sustainable jobs for local citizens.

THERE ARE TWO PRIMARY INTERRELATED

ASPECTS TO THIS EFFORT:

MANGROVE FOREST RESTORATION

The Marismas Nacionales (MN) is located on the Pacific coast of Mexico south of Mazatlan and north of Puerto Vallarta. It is the largest single expanse of mangroves on the Pacific coast of Mexico and all of the Americas and accounts for 20% of the mangrove area in Mexico. The highly productive MN provides a myriad of ecosystem services, including nursery and spawning habitat for numerous species of fish and shellfish that support a valuable fishery; important overwintering habitat for migratory birds; and food, material, and income for people that live in the area. Besides its biological importance, the extensive mangrove forests of the MN represent a large carbon resource. Mangroves are among the most carbon-rich forests in the world and substantially contribute to reducing atmospheric CO2 and slowing the rate of climate change. Despite its ecological importance and designation as a RAMSAR site and UNESCO biosphere reserve, the MN has lacked specific conservation strategies. Large tracts of the MN mangrove ecosystems have been eliminated or altered by development for agriculture, conversion to shrimp farms, dams and water diversion of freshwater tributaries, construction of a navigation channel, and deforestation for construction and firewood.

EcoWB with partners in Mexico (Pronatura Noroeste and the National Autonomous University of Mexico (UNAM)) have been involved in efforts to restore and protect the mangrove forests in the MN. The overall project comprises two related components:

1. Planning and implementing mangrove conservation and restoration projects,
2. Investigation of the feasibility of a carbon-crediting program derived from those projects to provide financial incentives to local communities to support conservation and restoration efforts and help fund restoration.

ACCOMPLISHMENTS

• March-April, 2014 — EcoWB and SFF co-organized and attended the Second International Mangroves as Fish Habitat Symposium, as part of the Western Division American Fisheries Society meeting in Mazatlán. This conference allowed us to convene local, regional, and international experts on mangroves to set the stage for our cooperative efforts on this project.
• April, 2014– Hosted strategy meeting to coordinate the project with representatives of UNAM, Comisión Nacional Forestal (CONAFOR), Pronatura Noroeste, World Wildlife Mexico and the University of Oregon. Field trip to Sinaloa mangroves with UNAM scientists to explore various mangrove restoration and assessment techniques.
• January, 2015– Negotiated and signed an MOU between EcoWB, SFF, and Pronatura Noroeste that committed the three parties to work together on mangrove restoration in Sinaloa and Nayarit, Mexico.
• April, 2016 — EcoWB volunteers met in San Blas, Nayarit with representatives of Pronatura Noroeste AC, Environmental Resources Management (ERM), UNAM, and regional forest and water management agencies to discuss strategies for mangrove protection and restoration. The visit included a workshop and a field trip to compare healthy and dead mangrove areas and restoration projects. Future plans included EcoWB and ERM assisting with technical assessment and monitoring, modeling of sequestered carbon, and potential development of a carbon crediting program.
• June, 2017–Developed a methodology to estimate mangrove biomass and carbon in the MN. Worked with Pronatura to assemble existing spatial data and published information on stand characteristics, including biomass and carbon content, and current restoration plans.
• December, 2017—Investigated process, data requirements, costs, and feasibility of obtaining carbon credits
• May, 2018—Briefed Pronatura, Fondo Noroeste, A.C. (FONNOR), and The Nature Conservancy (Mexico) on the results of carbon estimation and crediting analysis.
• Ongoing–Current efforts are focused on developing a bio-physical-social assessment to guide future conservation efforts including restoration plans.

MANGROVE FISHERIES RESTORATION AND MANAGEMENT

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 artisanal 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