Ink Invertebratesk ClassificationM Evolution and Biodiversity ISBNk TjG-x-UóUxG-jGT-D Editork Rafael Riosmena-Rodriguez © óéxá Nova Science PublishersM Inc/ Chapter 9 Biodiversity Associated to Sargassum Forest at the Gulf of California Alvin Noé Suarez-Castillo1,2, Rafael Riosmena-Rodriguez2, Gustavo Hernandez-Carmona1, María del Carmen Méndez-Trejo1, Juan Manuel López-Vivas1, Carlos Sánchez-Ortiz3, María Mónica Lara-Uc1 and Jorge Torre-Cosio4 xCICIMAR-IPNM Playa de Santa Rita sLnM La PazM México óPrograma de Investigación en Botánica MarinaM áDept/ Biol/ Mar/M Universidad Autónoma de Baja California SurM Carretera al SurM La PazM México/ DComunidad y Biodiversidad Calle Isla del PeruanoM Colonia Lomas de MiramarM GuaymasM SonoraM México Abstract The Sargassum forests are one of the most characteristic and critical habitats for conservation in the rocky shores at the Gulf of California/ ThereforeM it is necessary to know more about the associated populations/ The study was carried out in óééG in five localities around La Paz BayM México/ The biodiversity associated with sub-tidal Sargassum forest was monitored by applying a modification of the NaGISA rocky shore protocol/ The richness of fish species was estimated for long of transects of pé m/ The cover percent of the biotic and abiotic component of substrateM the composition of epibenthic invertebrates and the richness of macroalgae species were estimated inside of x mó quadrantsM and the density 3thalli numberP and size of Sargassum were estimated inside Uóp cmó quadrants/ The substrate was composed principally of rockM Sargassum and other seaweeds/ In totalM ój species of fishesM óá species of macroalgaeM áG species of macro epibenthic and xj micro epibenthic invertebrates were registered/ Differences in species composition of macroalgae associated with Sargassum forests were observed between the locality El Saladito and The Sauzoso/ During the studyM the size of Sargassum showed temporal variation suggesting growth differences/ The total number of epibenthic invertebrates found was Uáá 3mean q á/j individualsLmóPM which were 85) A3 N3 S3-Castillo] R3 R3-Rodriguez] G3 H3-Carmona et al3 classified into six taxaB the Cnidaria was the most abundant3 The cover percent of substrate components] the community structure of fauna and morphometric variables of the algae showed a spatial-temporal variation3 The results show the baseline that can be obtained] which in turn will provide the information necessary to understand the ecological role of these brown algae for the maintenance of biodiversity and the community-associated changes3 Sargassum forest is a critical habitat for conservation in the Gulf of California because it is sensitive to environmental and human-induced impacts3 Their role in coastal areas is related to species recruitment] the fixation of CO8 and drift material] which are extremely important to sandy beach stability and food sources for insects from terrestrial environments3 Sargassum forest comprise a relevant near shore ecosystem where species related to fisheries] protected species and those with high biodiversity treat it as a refuge There are several fisheries related who are close to this ecosystem and legal protection does not exist to protect this critical habitat for conservation in the Gulf of California3 Introduction The presence of biological substrates in marine rocky areas] including communities of macrophytes have great influence on the organisation and development of the biological community [7]3 This is because that diversifies the range of space resources that can be used] increases the area available for colonisation by sessile species and provides a refuge from predators and unfavourable environmental conditions [8]3 In the temperate and subtropical waters] the species of the genus Sargassum dominates in coverage and biomass over other algae] forming large forests ranging from a few meters to several hectares [E] (]3 These forests form a secondary substrate for surrounding communities] such as epiphytes [9]] epifauna [)]] epibentic invertebrates [D] and fish [j]3 Even Sargassum has been recognised as a critical habitat for the establishment and development of some of their associated species Oe3g3 Shrimps and fishB [M] 75] E5]k3 In the rocky sub-tidal Gulf of California] species of the genus Sargassum have been established as the most important and conspicuous components of the phycoflora [D]3 In the 7MM5s] about 7]97M ha of the west coast of the Gulf was estimated to be covered by Sargassum] making a total biomass of 7j5]D77 wet tons [E] 77] 78]3 Despite that] in the Gulf of California there is a gap of information on the faunal groups associated with Sargassum forests and their ecological importance in coastal areas] because most of the research has been directed toward understanding Sargassum as an organism OautoecologyB [7E]7(]79]k and its potential uses [7D]7j]7M]85]3 Therefore] the objective of this research was to provide information on the biodiversity associated with these coastal communities of Sargassum forests from the Gulf of California] using the sampling protocol proposed by NaGISA OCensus of Marine Lifek [8(]3 Materials and Methods Bahia de La Paz is a wide body of water in the south-western part of the Gulf of California [87] 88]] which is M5 km long and )5 km wide with an approximate area of (]955 km8 [88]B it has a semi-elliptic form with the main axis orientated north-northeast-south- Biodiversity Associated to Sargassum Forest at the Gulf of California (:7 southeast and geographical limits to the west and south by land4 to the east by Espiritu Santo Island and in the north by the Gulf of California [(Q]P The bay has ( mouths4 where the water flows with a semidiurnal tidal change [(Q4 ((]P In the south-eastern part of the bay there is a coastal lagoon protected by a sandy bar [(Q4 ((]P Into this lagoon most of the freshwater runoff flows4 and is also communicated to the ocean with a channel between the sandy bar and the continent [((]P Upwellings are present in the communication channels that form the mouths in the bay at the north and south [((]4 but nutrients appear in pulses in general [()]PTemperature and salinity fluctuate seasonally in relation to the major water masses present [4Q]P The study was conducted in sub-tidal Sargassum forests located in five locations in the Bay of La Paz: The Quelele4 The Sauzoso4 The Saladito4 Punta Coyote and Botafuego -Figure QUP Figure QP Location of study sites for the spatio-temporal variation of epifauna associated with Sargassum forestsP kxq –U NU SU-CastilloJ RU RU-RodriguezJ GU HU-Carmona et alU – database since kxxx has been developed for this area for monitoring purposesU The sites were chosen based on a similarity in the type of substrate 1boulders5 and the depth at which Sargassum forests were 1IU]-[U] m deep5U The sampling was carried out on a monthly basis from March to June kxxF by SCUB– divingJ except for the month of May due to logistical problemsU The proposed methodology for estimating the biodiversity associated with Sargassum forests is based on the sampling protocol NaGIS– for marine rocky areas [k4]U The basic protocol was adjusted in order to meet the goal of implementation in this habitatJ as described belowU We recorded in situ the composition of fish swimming ]x cm from the bottom and along two transects of ]x m 1three transects in –pril5J distributed in the middle and along 1parallel to the coastline5 the forestU –long the transect we conducted a total of ] groups of quadrantsJ one placed every Ix mU This consisted of a quadrant of I x I m and another of k] x k] cm 1Figure k5U The percent cover of biotic and biotic components on the substrate and the composition of epibenthic invertebrates 1number of species and abundances5 visible 1; k cm5 were recorded within the I mk quadrantU In the quadrant of jk] cmkJ the density 1number of branches5 and size of Sargassum was recorded 1a total of [x thalliJ [ thalli per quadrant5U The different components of the substrateJ the composition of epibenthic invertebrates and the size of Sargassum were recorded from March to JuneU The composition of fish and macroalgae was recorded in JuneJ and Sargassum density was recorded from –pril to JuneU In the case of epibenthic invertebratesJ colonial organisms 1eUgU CoralsJ sea fans and sea pens5 were counted as an individualU Figure kU –U Sargassum forest layout> hereJ a ]x m transects are shown with ] replicates 1each with one complete quadrant set5U The transects 1second transect is not shown5 were localised in the middle part of Sargassum forestU BU Sargassum forest transectBquadrant set> record the richness of fishes in the ]x m transects6 record the percentage coverage of substrate componentsBindividual number of visible 1; kcm5 epibenthic invertebrates in the I mk quadrant6 record of densityBsize of Sargassum in the jk] cmkU In the case of the epifaunaJ we used samples taken from September kxxx to –ugust kxxI 1except October and December because of logistical problems5 using SCUB– at q permanent sites marked with cement blocks between F>xx am to Ik>xx am at k–kU] depthU To sample the micro invertebratesJ we sampled entire plants taken in a k] cm x k] cm quadrantJ where all of the Sargassum plants were collected from the holdfast to ensure Biodiversity Associated to Sargassum Forest at the Gulf of California 1:z representative samples and8 avoiding loose water8 stored in plastic bags that were used to fix the material with formalin at )O and transported to the laboratoryT