Project: Connectivity among populations of marine benthic mollusks, case study: abalone Haliotis spp

Abalone fisheries is one of the most important economic activities in the western coast of the Baja California peninsula, particularly in the region between Isla Cedros, B.C. and Bahía Magdalena, B.C.S. Fisheries in this area comprises two main species: blue abalone, whose scientific name isHaliotis fulgens and the yellow one (Haliotis corrugata). There are other species in the area, such as black, Chinese, and red abalone; their abundances are minimal, though.

Unfortunately, over exploitation, poaching, and environmental changes have contributed to a reduction in their populations. This is why it is necessary to design fishery management strategies to promote their recovery.  For this purpose, it is required to know different aspects of their biology and ecology (in other words, their interaction with the environment and with other marine species).

This project deals with two topics:

1. Connectivity among populations, and

2. Species identification with genetic markers.

1) The objective of dealing with connectivity in this project is to know how these two abalone shoals (abalone aggregates in a determined rocky area) are connected or communicate among themselves. Let us imagine two rocky shoals that are separated by 500 m of sand: it is not very likely that abalone from one shoal move by the bottom of a shoal to another one because abalone prefer to be “attached” to the rocks; however, is it possible for larvae to move from one shoal to another one?

Depending on environmental conditions (strength and direction of currents, time larvae last floating in water, availability of space on rocks for larvae to attach and on predation on their way), it is feasible that larvae produced in a shoal during reproduction settle in a neighboring shoal and develop up to adult abalone.

Therefore, if we know how two or more shoals connect, we will have better information to decide on which to fish and how much can be fished our. However, how do we know if an abalone (be either larva, juvenile or adult) had its origin in the shoal it was found or if it came from another one?

To solve this problem, what we do in this project is identify the abalone and their larvae through “genetic prints”. The genetic prints are like fingerprints that are unique but “made” of DNA. This way we look for specific genetic prints that indicate if an abalone had its origin in one or in another site. The powerful DNA analysis technique also allows us to identify other mollusk species that have similar larvae to those of abalone, which helps as a differentiation tool when performing larval studies in the habitat areas of abalone.

2) With respect to species identification with genetic markers, the idea is to find certain types of DNA to allow discriminating an abalone from a winkle and avoid being swindled.

All Sudcalifornians know that abalone is exquisite and expensive seafood that is rarely found in the local market. Unfortunately, different natural phenomena and over exploitation (particularly illegal fishing) has decreased wild populations, which force us to take several control measurements for their recovery. Because this is not an exclusive problem for our country but it also affects other countries that are abalone producers (Australia, Japan, South Africa), a decrease in natural populations and a high demand have favored a high rise in price in international markets which makes it more profitable for local cooperatives to export the product instead of selling it in México.

This popularity and high price of abalone has been the reason for “pirate” products, that is to say canned products of other mollusks (usually winkle or limpet) that are sold as abalone or as “abalone type” product. This is why it is important to develop techniques that will allow the identification of the canned product to know what product we are buying.

For this purpose, we use genetics and DNA technology, which consist on extracting DNA from each abalone, isolating specific fragments and comparing them. Once we define the composition and length of the fragments of each one of the species, it will be possible to differentiate them, even if they have been canned.

As a result of this research project we can identify if a can contains Mexican abalone and what species, in other words, if it is blue, yellow or red abalone, or we can determine if the blue abalone from Isla Guadalupe is slightly different from the one from Bahía Tortugas, but not different from the one from Bahía Magdalena.

This information plus the one obtained by our colleagues from CIBNOR and other institutions, including fisheries cooperatives, will contribute to better abalone fishery exploitation and better control measurements to reduce illegal fishing.

The next step in our study is to genetically identify the other mollusk species that are canned to be able to differentiate the product which is really abalone. This work will not only contribute to improve surveillance on the exploitation of this fishery resource, but will also help in providing the appropriate information rendered to consumers to avoid being swindled.

Abalone (Haliotis fulgens)	Limpet "abalone type"