Laguna Ojo De Liebre Research Articles

Hermaphroditism and the impact of environmental variables on atresia prevalence in the pen shell Pinna rugosa

The pen shell fishery in northwest Mexico is based on reproductive quota, but the reproductive biology of Pinna rugosa, an economically valuable species, has not yet been documented in its main fishery area. The aim of this study was to evaluate the reproductive cycle of P. rugosa, determine the prevalence of atresia and hermaphroditism, and estimate the effect of environmental variables on its reproduction during 2015. Atresia is part of the reproductive cycle in which the cells undergo degeneration. It generally occurs after spawning to reabsorb compounds but it can also occur from the early stages of gametogenesis, affecting fertilization and recruitment. Gonad samples and environmental parameters were collected monthly from a commercial bank at Laguna Ojo de Liebre (Baja California Sur, Mexico) from January to December 2015. Shell height, sex, gonadal development stages, and atresia prevalence were recorded. The results showed that 14% of the individuals were females, 19% were males, and 67% were hermaphrodites, with 3 forms of functional hermaphroditism. Gonadal inactivity occurred in January, February, November, and December, coinciding with lower temperatures and higher chlorophyll a concentrations. Most individuals spawned in June and July. Calculation of a monthly gonad index revealed that gonad development was positively related to environmental variables (R2 = 0.54). Atresia was observed from March to October and was positively related to environmental conditions (R2 = 0.81). The high prevalence of atresia during periods of high temperature and food scarcity suggests that these environmental parameters can affect the reproductive activity of P. rugosa, and have recruitment and fishery productivity implications.

Pontonia margaritaVerrill, 1869 (Decapoda: Caridea: Palaemonidae) as a symbiont ofPinna rugosaSowerby, 1835 (Mollusca: Bivalvia) on both coasts of the Baja California Peninsula, Mexico

AbstractMany caridean shrimps live in symbiosis with bivalves, the shrimps finding refuge and food in the mucus in their host’s mantle cavity. We report for the first time the presence of Pontonia margarita Verrill, 1869 on both coasts of Baja California Peninsula, Mexico, as a symbiont of the pen shell Pinna rugosa Sowerby, 1835. The symbiont was found in Laguna Ojo de Liebre (LOL), which faces the Pacific Ocean, and in Bahía Concepción (BC), on the eastern coast facing the Gulf of California. A total of 569 specimens of Pinna rugosa were studied, 472 from LOL (104–277 mm shell length (SL)) and 97 from BC (130–234 mm SL). A total of 376 Pontonia margarita individuals were extracted in LOL (19–41 mm total length (TL)) and 41 in BC (20–48 mm TL). The prevalence of Pontonia margarita was 46% in LOL and 28% in BC. The regression analyses for both sexes of Pontonia margarita showed a high correlation between TL and total weight and abdominal length and TL. The data showed a moderate correlation between TL and the length of the major and minor chelae, and TL and length of the minor chela. There was no significant relationship between biometric parameters of the host and the symbiont. The presence of gravid females of Pontonia margarita (52% in LOL and 39% in BC) in shells suggests reproduction during autumn.

Biological indicator of warming events: Presence of the Cortez angelfish Pomacanthus zonipectus at temperate conditions of Bahía de San Quintín, Baja California, México

An individual of the Cortez angelfish, Pomacanthus zonipectus (Gill, 1862) was obtained at the temperate Bahía de San Quintín, Baja California, México (Lat. 30.428343, Long. 115.987014), on May 15, 2021. All counts, morphological descriptions, and colors of the specimen caught agree with the previous descriptions for the species P. zonipectus. The Cortez angelfish is a tropical fish species, and its presence at the temperate environment may possibly be associated with warming events, The Blob-El Niño 2013-2016, or the most recent moderate El Niño 2018-2019. This occurrence constitutes the first record for the Cortez angelfish in the San Quintín area, northern Pacific off Baja California, and after thousands of samplings with different fishing gears beginning in 1993. The Cortez angelfish was recently recorded in August 25, 2016 as a new occurrence in Laguna Ojo de Liebre, Baja California Sur, México, also in the same warming event of The Blob-El Niño 2013-2016; from Ojo de Liebre to Bahía de San Quintín represents a northward movement of 355 kilometers and a new record in its distribution.

Photochemical changes during rehydration of an intertidal cyanobacterial mat exposed to variations in salinity and light intensity.

This study focuses on a Lyngbya cf. aestuarii dominated mat community from the intertidal zone of the Laguna Ojo de Liebre, Baja California Sur. In this environment, the mat is desiccated for several days between spring tides. While the mats were desiccated, photosynthetic activity was absent but recovered rapidly (~3 h) upon rehydration. It has been shown previously that the rate of photosynthetic recovery is dependent on both light intensity and salinity. In the current study, photosynthetic recovery was measured based on chlorophyll a fluorescence using pulse amplitude modulated (PAM) fluorometry. Upon the addition of water, photosystem II (PSII) complexes recovered the capacity for reaction centre excitation. However, these functional centres were initially closed. Respiratory activity early in recovery probably reduced the plastoquinone pool through the shared use of part of the photosynthetic transport chain, thus temporarily blocking electron transport downstream of PSII. The time that PSII complexes remained closed increased with light intensities above saturation. This condition is potentially damaging to the cyanobacteria since the exposure of closed PSII centres to high light intensities can lead to the production of singlet oxygen. After this initial lag period, PSII centres opened rapidly indicating an increase in the flow of electrons from PSII to PSI. The rate of photosynthetic recovery appeared to be limited primarily by the relatively slow return of functional PSII. Photosynthetic recovery rates were slower in salinities greater than those that naturally occur in the intertidal zone.

New fish species added to the ichthyofauna of Laguna Ojo de Liebre, Baja California Sur, México

The Laguna Ojo de Liebre (Scammon’s lagoon) is the iconic sanctuary of the Pacific gray whale and belongs to the El Vizcaino Biosphere Reserve in Baja California, México. From June 2015 to August 2016, six seasonal visits were conducted on the ichthyofauna in seven sites of the lagoon. By diving, trapping, hook & line, and gillnet commercial fishing, a total number of 39 fish species was identified belonging to 25 families. In this study a total number of eight fish species is added to the first two existing 20-year-old lists: the Gymnothorax mordax (Ayres, 1859), Apogon sp. Pomacanthus zonipectus (Gill, 1862), Balistes polylepis (Steindachner, 1876), Pareques viola (Gilbert 1898), Caranx sp., Sphoeroides lobatus (Steindachner, 1870), and the Icelinus sp. During 2015-2016, two anomalous events warmed the lagoon, and possibly, it contributed to the fish species movement from the adjacent tropical or subtropical zones. Ichthyofauna from Laguna Ojo de Liebre is reported here before the installation of reef modules as a refuge for red lobster and fish aggregation.

Variación espacial y temporal de la infestación de la concha por Polydora sp. (Spionidae: Polychaeta) sobre la almeja mano de león (Nodipecten subnodosus) en la laguna Ojo de Liebre, Baja California Sur

In this study we evaluated the degree of infestation of Polydora sp. in Nodipecten subnodosus (lion's paw scallop). This research was carried out in laguna Ojo de Liebre, Baja California Sur, Mexico, quantifying the damage and growth of the clam for three years. A total of 10 samplings were carried out between January 2013 and October 2015, collecting 30 organisms by sampled at the banks Zacatoso, Chocolatero, El Dátil and La Concha. There were between 0 and 13 blisters per shell, 1.77 bisters shell-1 on average. The number of blisters was higher in the clams of the banks Chocolatero and Zacatoso, while in the banks El Dátil and La Concha, not only did the infestation decrease, but the variation intervals were smaller. Banks with smaller clams also recorded the largest number of blisters, mainly in Chocolatero. Although the maximum number of blisters occurred in January 2013, May 2014 and March 2015, the overall trend was for a reduction in polychaete infestation and clams over the length of study time.

Revisiting N₂ fixation in Guerrero Negro intertidal microbial mats with a functional single-cell approach.

Photosynthetic microbial mats are complex, stratified ecosystems in which high rates of primary production create a demand for nitrogen, met partially by N2 fixation. Dinitrogenase reductase (nifH) genes and transcripts from Cyanobacteria and heterotrophic bacteria (for example, Deltaproteobacteria) were detected in these mats, yet their contribution to N2 fixation is poorly understood. We used a combined approach of manipulation experiments with inhibitors, nifH sequencing and single-cell isotope analysis to investigate the active diazotrophic community in intertidal microbial mats at Laguna Ojo de Liebre near Guerrero Negro, Mexico. Acetylene reduction assays with specific metabolic inhibitors suggested that both sulfate reducers and members of the Cyanobacteria contributed to N2 fixation, whereas 15N2 tracer experiments at the bulk level only supported a contribution of Cyanobacteria. Cyanobacterial and nifH Cluster III (including deltaproteobacterial sulfate reducers) sequences dominated the nifH gene pool, whereas the nifH transcript pool was dominated by sequences related to Lyngbya spp. Single-cell isotope analysis of 15N2-incubated mat samples via high-resolution secondary ion mass spectrometry (NanoSIMS) revealed that Cyanobacteria were enriched in 15N, with the highest enrichment being detected in Lyngbya spp. filaments (on average 4.4 at% 15N), whereas the Deltaproteobacteria (identified by CARD-FISH) were not significantly enriched. We investigated the potential dilution effect from CARD-FISH on the isotopic composition and concluded that the dilution bias was not substantial enough to influence our conclusions. Our combined data provide evidence that members of the Cyanobacteria, especially Lyngbya spp., actively contributed to N2 fixation in the intertidal mats, whereas support for significant N2 fixation activity of the targeted deltaproteobacterial sulfate reducers could not be found.

Carry-over effects of winter location contribute to variation in timing of nest initiation and clutch size in Black Brant (Branta bernicla nigricans)

ABSTRACT. We assessed carry-over effects from winter location on timing of nest initiation and clutch size of Black Brant (Branta bernicla nigricans) using observations of individually marked brant breeding at the Tutakoke River colony in Alaska, and wintering along a latitudinal gradient at three areas on the Pacific coast of Baja California: northernmost Bahia San Quintin (BSQ), Laguna Ojo de Liebre (LOL), and southernmost Laguna San Ignacio (LSI). Black Brant initiated nests according to a north—south trend in winter location, although year was a stronger predictor of initiation date than was wintering site. Female Black Brant that wintered at BSQ initiated nests 2.2 days earlier than females from LSI. Conversely, Black Brant showed only a weak south—north trend in clutch size; individuals from LSI laid slightly larger clutches than individuals from BSQ, probably because a smaller proportion of only high-quality females from the southernmost wintering area in Baja California were able to attain the nut...

Carryover Effects Associated with Winter Location Affect Fitness, Social Status, and Population Dynamics in a Long-Distance Migrant

We used observations of individually marked female black brant geese (Branta bernicla nigricans; brant) at three wintering lagoons on the Pacific coast of Baja California-Laguna San Ignacio (LSI), Laguna Ojo de Liebre (LOL), and Bahía San Quintín (BSQ)-and the Tutakoke River breeding colony in Alaska to assess hypotheses about carryover effects on breeding and distribution of individuals among wintering areas. We estimated transition probabilities from wintering locations to breeding and nonbreeding by using multistratum robust-design capture-mark-recapture models. We also examined the effect of breeding on migration to wintering areas to assess the hypothesis that individuals in family groups occupied higher-quality wintering locations. We used 4,538 unique female brant in our analysis of the relationship between winter location and breeding probability. All competitive models of breeding probability contained additive effects of wintering location and the 1997-1998 El Niño-Southern Oscillation (ENSO) event on probability of breeding. Probability of breeding in non-ENSO years was 0.98 ± 0.02, 0.68 ± 0.04, and 0.91 ± 0.11 for females wintering at BSQ, LOL, and LSI, respectively. After the 1997-1998 ENSO event, breeding probability was between 2% (BSQ) and 38% (LOL) lower than in other years. Individuals that bred had the highest probability of migrating the next fall to the wintering area producing the highest probability of breeding.

Nuclear and mtDNA lineage diversity in wild and cultured Pacific lion-paw scallop, Nodipecten subnodosus (Baja California Peninsula, Mexico)

Pacific lion-paw scallops were collected from natural aggregations in Laguna Ojo de Liebre (Pacific Ocean), the Gulf of California, and from aquaculture facilities for genetic diversity analyses. Mitochondrial DNA sequencing uncovered two highly supported clades separated by 2.5% divergence. Data from ten microsatellite markers suggest individuals from these mitogroups are introgressed, raising questions about the mitotype origin. Some evidence suggests gene flow between La Paz and Ojo de Liebre; otherwise the Gulf of California and Ojo de Liebre are acting as two distinct populations. It is unclear whether translocations between sites have influenced the observed genetic structure or whether gene flow has been facilitated by past geologic events. Finally, scallops spawned for aquaculture are unique from the wild and have significantly less diversity. These results warrant the attention of managers and producers who should work to monitor and conserve genetic diversity in both wild and aquaculture populations.Electronic supplementary materialThe online version of this article (doi:10.1007/s00227-010-1534-1) contains supplementary material, which is available to authorized users.

Long-term monitoring of black turtles Chelonia mydas at coastal foraging areas off the Baja California Peninsula

Monthly in-water monitoring was conducted at 5 foraging areas off the Baja California Peninsula, Mexico, from 2001 to 2006 to assess black turtle population status. Turtles were captured with entanglement nets, size (straight carapace length, SCL) and weight of each individual were recorded and turtles were tagged on both rear flippers. A total of 1238 turtles were captured, involv- ing 6309 h of effort. Of this total, 937 ind. were marked and 155 were recaptured. SCL ranged from 30 to 95.5 cm; immature turtles accounted for >94% of the total catch and were dominant at all sites. However, size class distribution varied among sites, and turtles from the Gulf of California were sig- nificantly larger than those caught in the Pacific. Catch per unit of effort (defined as the number of turtles caught per 100 m of net soaking for 24 h) varied from 1.79 at Bahia Magdalena to 17.35 at Punta Abreojos. Mean (±SD) annual growth rate for black turtles was 2.27 ± 0.71 cm yr -1 , with the lowest and highest growth rates in Bahia Magdalena (1.37 ± 0.71 cm yr -1 ) and Laguna Ojo de Liebre (3.05 ± 2.23 cm yr -1 ), respectively. Lack of recaptures from adjacent sites and multiple recaptures of specimens at the site of origin over several years indicate a low connectivity among foraging areas and a high site fidelity. Hence, strengthening local protection is imperative to the recovery of black sea turtle populations.

Immature East Pacific Green Turtles (Chelonia mydas) Use Multiple Foraging Areas off the Pacific Coast of Baja California Sur, Mexico: First Evidence from Mark-Recapture Data

Since 2001, Grupo Tortuguero has been conducting monthly in-water monitoring of East Pacific green turtles (Chelonia mydas), also known as black turtles, at four neritic foraging areas (Bahia Magdalena, Laguna San Ignacio, Punta Abreojos, Laguna Ojo de Liebre) along the Pacific coast of Baja California Sur, Mexico. Extensive tagging (883 turtles tagged of 1,183 turtles captured) and recaptures (154 tagged turtles recaptured at least once) at these four areas suggest that immature East Pacific green turtles show strong site fidelity to their neritic foraging grounds. However, in 2007, we recaptured two immature turtles, one in Laguna San Ignacio and the other in Bahia Magdalena, that were both originally captured in Punta Abreojos. To our knowledge, this represents the first direct evidence of immature East Pacific green turtles using multiple foraging areas along the Baja California Peninsula. This report highlights the importance of long-term monitoring efforts that encompass several habitats on a relatively large spatial scale (~80 km between Punta Abreojos and Laguna San Ignacio and ~300 km between Punta Abreojos and Bahia Magdalena) to better understand the movements and habitat use of immature East Pacific green turtles on their neritic foraging areas.

Diurnal Abundance, Foraging Behavior and Habitat Use by Non-Breeding Marbled Godwits and Willets at Guerrero Negro, Baja California Sur, México

Seasonal variation in abundance, time activity budgets and foraging behavior of non-breeding Marbled Godwits (Limosa fedoa) and Willets (Tringa semipalmata) were compared at four sites at the Laguna Ojo de Liebre—Guerrero Negro saltworks complex, Baja California, Mexico. Habitat use varied between species, seasons and sites. Marbled Godwits (182 ± 44.1 individuals per site) were more abundant than Willets (70 ± 16.1 individuals per site), reflecting their overall pattern in northwestern Mexico. Overall abundance diminished throughout the season (270 ± 69 individuals per site in Oct–Nov, 85 ± 21 in Dec–Jan and 60.2 ± 24 in Feb–Mar), although it remained high at mudflat. Consistent with bill length, Willets foraged mostly by pecking, while Marbled Godwits did so mostly by probing (proportion of pecks: 0.95 ± 0.17 and 0.4 ± 0.27, respectively). Marbled Godwits changed their time activity budgets through the wintering season: time devoted to vigilance changed from 8–23% in Oct–Nov, to 0.4–8% in Feb–Mar whereas time devoted to feeding changed from 12–40% in Oct–Nov to 59–74% in Feb–Mar. This pattern seems to reflect a change in priorities; surviving early in the season and accumulating energy to migrate, later. In both species, differences in use of habitat appeared to be related to site characteristics such as substrate hardness and risk of predation. The mudflat was the site most used and the saltmarsh, the least used. Some individuals in both species used the more risky saltmarsh, but increased the time devoted to vigilance. Thus, habitat quality for non-breeding shorebirds depended on both benefits and costs for foraging birds, and habitat choice by specific individuals was complex and probably involved condition- or state-dependent tradeoffs that balanced metabolic requirements, safety priorities, and, perhaps, social status or dominance.

Diversity and Stratification of Archaea in a Hypersaline Microbial Mat

The Guerrero Negro (GN) hypersaline microbial mats have become one focus for biogeochemical studies of stratified ecosystems. The GN mats are found beneath several of a series of ponds of increasing salinity that make up a solar saltern fed from Pacific Ocean water pumped from the Laguna Ojo de Liebre near GN, Baja California Sur, Mexico. Molecular surveys of the laminated photosynthetic microbial mat below the fourth pond in the series identified an enormous diversity of bacteria in the mat, but archaea have received little attention. To determine the bulk contribution of archaeal phylotypes to the pond 4 study site, we determined the phylogenetic distribution of archaeal rRNA gene sequences in PCR libraries based on nominally universal primers. The ratios of bacterial/archaeal/eukaryotic rRNA genes, 90%/9%/1%, suggest that the archaeal contribution to the metabolic activities of the mat may be significant. To explore the distribution of archaea in the mat, sequences derived using archaeon-specific PCR primers were surveyed in 10 strata of the 6-cm-thick mat. The diversity of archaea overall was substantial albeit less than the diversity observed previously for bacteria. Archaeal diversity, mainly euryarchaeotes, was highest in the uppermost 2 to 3 mm of the mat and decreased rapidly with depth, where crenarchaeotes dominated. Only 3% of the sequences were specifically related to known organisms including methanogens. While some mat archaeal clades corresponded with known chemical gradients, others did not, which is likely explained by heretofore-unrecognized gradients. Some clades did not segregate by depth in the mat, indicating broad metabolic repertoires, undersampling, or both.

EFFECTS OF SALINITY AND LIGHT INTENSITY ON THE RESUMPTION OF PHOTOSYNTHESIS IN REHYDRATED CYANOBACTERIAL MATS FROM BAJA CALIFORNIA SUR, MEXICO1

Lyngbya mats in the intertidal of the Laguna Ojo de Liebre are metabolically active for only a few days every 2 weeks during spring tides, with environmental conditions varying greatly during these periods of hydration. Pulse amplitude modulated fluorometry (PAM) and oxygen measurements were used to measure photosynthetic activity during the first few hours after rehydration under various light intensities and salinities. Upon rehydration, a transitory maximum in respiratory activity (10–30 min) occurred before the resumption of photosynthesis, which could recover in about 2 h. Salinities outside the mats' natural range (35–50 psu) were detrimental to photosynthetic recovery. Both high (100 psu) and low (0–10 psu) salinities slowed recovery as well as lowered the overall photosynthetic yield. Photosynthesis was initiated earlier and recovered more rapidly with increasing light intensity. In addition, the positive effect of light on rates of recovery was disproportionately greater at lower salinities (10–25 psu) where high light (500 W·m−2) counteracted the negative effects of low‐salt stress early in recovery. However, higher light intensities became photoinhibitory later in recovery (>2 h). Photosynthesis did not recover uniformly within the mat. Filaments deeper in the mat most likely recovered later than those near the surface due to high light attenuation. The ability of the mats to tolerate desiccation and take advantage of hydration periods even when conditions are suboptimal enables these mats to predominate in the intertidal environment.

ALINITY TOLERANCE AND RESISTANCE OF THE PACIFIC LION'S PAW SCALLOP (NODIPECTEN SUBNODOSUS) AND THE RELATIONSHIPS WITH SPECIES DISTRIBUTION AND DENSITY IN A COASTAL LAGOON

Abstract Salinity tolerance and resistance of the Pacific lion's paw scallop Nodipecten subnodosus, using the median lethal concentration method (LC50) and a gradual change method were measured. We also attempted to demonstrate whether salinity and temperature, pH, dissolved oxygen and turbidity control the distribution and densities of species within a coastal lagoon (Laguna Ojo de Liebre, Mexico). The upper and lower LC50 of this scallop were determined in the laboratory at predetermined times over 4 days (96 h) when exposing specimens to salinities of 15, 20, 25, 30, 37, 42, 47, 50 and 60 ppt. The upper and lower salinity resistances were studied by subjecting the specimens to either increases or decreases of salinity by 3 ppt every 3 days, departing from a normal salinity of 37 ppt. Salinity, temperature, pH, dissolved oxygen, and turbidity of the water close to the bottom were measured once a month from January 2001 to March 2004 at 20 stations located along the shore of the lagoon. Results showed no...

Mitochondrial DNA variation among Eastern North Pacific gray whales (Eschrichtius robustus) on winter breeding grounds in Baja California

In this study, we used genetic data to investigate the role of female-directed philopatry in winter habitat use patterns among female eastern North Pacific gray whales (Eschrichtius robustus) in calving years. Analysis of 306 base pairs of the mitochondrial DNA control region for 83 animals sampled from two geographically discrete winter breeding and calving lagoons revealed 28 haplotypes (nucleotide diversity (π) = 0.02, haplotype diversity (h) = 0.95). Significant differences in haplotype (FST) and nucleotide (ΦST) frequencies were detected between Laguna San Ignacio cows (n = 42) and a random sample of non-lagoon females (n = 25; FST= 0.064, p < 0.01; ΦST= 0.041, p = 0.043) and between cows and single females (n = 11; FST= 0.027, p = 0.044; ΦST= 0.088, p = 0.034) in Laguna San Ignacio. Significant differences in haplotype, but not nucleotide, frequencies were also detected between cows in Laguna Ojo de Liebre (Scammon's Lagoon) and non-lagoon females (n = 10; FST= 0.074, p < 0.01) and between single females (n = 11) or adult males (n = 13) in Laguna San Ignacio and their non-lagoon counterparts (nfemales= 25, FST= 0.07, p < 0.01; nmales= 28, FST= 0.08, p < 0.01). These data suggest that all animals exhibit some level of site fidelity to their natal lagoons as adults, and that the eastern North Pacific gray whale population may be substructured on the population's wintering grounds.

Spatial and seasonal variation of macroalgal biomass in Laguna Ojo de Liebre, Baja California Sur, México

Laguna Ojo de Liebre is part of El Vizcaino Biosphere's Reserve, one of the largest protected natural areas in the world. The contribution of seaweeds to the lagoons' total biomass had not been previously quantified. The purpose of this study was to evaluate the spatial and temporal variations of seaweed biomass in the lagoon. Seaweed samples were taken every season during 1995 at six sampling stations distributed throughout the lagoon. Total specific biomass of seaweeds was at its peak in the summer, and minimum in spring. The highest total annual biomass was found at Isla Brosa in the lagoon's central portion, and the lowest in El Datil at the head. The seasonal and spatial variation of biomass in the lagoon is related with species richness and environmental parameters. Potentially important species in terms of biomass, wide spatial and temporal distribution, and potential use were: Spyridia filamentosa, Entheromorpha clathrata, Dasya baillouviana, Hypnea valentiaeand Sargassum sinicola .Using PCA three groups of stations were defined: one chiefly at the lagoon's mouth, another comprised the islands in the central portion, and the last in the lagoon's head. Palabras clave: Tendencias espaciales, Laguna Ojo de Liebre, Nyctiphanes simplex, Seaweed, spatial, seasonal

Past and present research on gray whale vocalizations

Eberhadt and Evans first recorded vocalizations of gray whales in 1967 in Laguna Ojo de Liebre, Mexico. Three and a half decades of bioacoustic research on gray whales has followed this groundbreaking work. Gray whales appear more vocal while at the southern breeding lagoons off Baja California and are least vocal at the northern feeding areas of the Bering, Chukchi, and Beaufort Seas. Ten different vocalizations have been identified on the breeding grounds, while only six different vocalizations have been recorded on the feeding grounds. Evans also conducted the first recordings of vocalizations of gray whales in captivity with his work on J.J. II in San Diego in 1974. Since then, the database of captive gray whale vocalizations has expanded with research on GiGi in 1997. From this review, an acoustic repertoire of at least 12 different types of vocalizations is suggested. Nevertheless, not all gray whale calls fall into obvious or distinct categories; thus, correlating specific behaviors with each vocalization type merits further study.

Lordosis in topsmelt Atherinops affinis (Ayres, 1860) (Teleostei: Atherinopsidae)

Se describe por primera vez un caso de lordosis (curvatura de la columna vertebral) en el pejerrey Atherinops affinis, a partir de un ejemplar recolectado en la Laguna Ojo de Liebre, Baja California Sur, Mexico.