Lunar phase and catch success of the striped marlin (Tetrapturus audax) in sport fishing at Los Cabos, Baja California Sur, Mexico

The influence of the lunar phases on the catch-per-unit effort (CPUE) of the striped marlin (Tetrapturus audax) captured by the Cabo San Lucas, Baja California Sur, Mexico sport-fishing fleet from October 1987 to June 1989 was analyzed. The information is from 3,377 fishing trips by 13 vessels that represent about 10% of the fleet. The analysis of the CPUE showed a maximum in January 1988 and a minimum in February 1989. Taking into account the knowledge of the factors that had influence on the fishing success is important in the resource management. No significant difference during the full moon compared with results during other lunar phases was found.     

Trophic interaction between striped marlin and swordfish using different timescales in waters around Baja California Sur,Mexico

Isotopic niche and resource partitioning were examined between striped marlin (Kajikia audax) and swordfish (Xiphias gladius) using stable isotope ratios from spine bone and muscle samples. The δ¹³C (¹³C/¹²C) and δ¹⁵N (¹⁵N/¹⁴N) values were measured in annual growth bands from fin spines and muscle collected from striped marlin and swordfish off Baja California Sur to evaluate the trophic interaction between these two species, the relative contribution of the main prey and the isotopic niche within two different timescales. Mean trophic level (TL) values were different when tissues were compared with the highest value found in muscle samples from K. audax. When TL was analysed in all growth bands for both species, no changes were detected throughout time, suggesting only minor differences in feeding habits between these species. We determined that Dosidicus gigas, Sthenoteuthis oualaniensis, and Ancistrocheirus lesueurii were the most important prey for both species, but the relative contribution of each of them to the diet differed. There is likely no trophic overlap between K. audax and X. gladius off Baja California Sur, as K. audax occupied a larger isotopic niche with more diverse prey than X. gladius.     

Investigating behaviour and population dynamics of striped marlin (Kajikia audax) from the southwest Pacific Ocean with satellite tags

Behaviour and distribution of striped marlin within the southwest Pacific Ocean were investigated using electronic tagging data collected from 2005-2008. A continuous-time correlated random-walk Kalman filter was used to integrate double-tagging data exhibiting variable error structures into movement trajectories composed of regular time-steps. This state-space trajectory integration approach improved longitude and latitude error distributions by 38.5 km and 22.2 km respectively. Using these trajectories as inputs, a behavioural classification model was developed to infer when, and where, 'transiting' and 'area-restricted' (ARB) pseudo-behavioural states occurred. ARB tended to occur at shallower depths (108 ± 49 m) than did transiting behaviours (127 ± 57 m). A 16 day post-release period of diminished ARB activity suggests that patterns of behaviour were affected by the capture and/or tagging events, implying that tagged animals may exhibit atypical behaviour upon release. The striped marlin in this study dove deeper and spent greater time at ≥ 200 m depth than those in the central and eastern Pacific Ocean. As marlin reached tropical latitudes (20-21 °S) they consistently reversed directions, increased swimming speed and shifted to transiting behaviour. Reversals in the tropics also coincided with increases in swimming depth, including increased time ≥ 250 m. Our research provides enhanced understanding of the behavioural ecology of striped marlin. This has implications for the effectiveness of spatially explicit population models and we demonstrate the need to consider geographic variation when standardizing CPUE by depth, and provide data to inform natural and recreational fishing mortality parameters.     

Eriogonum (Polygonaceae) novelties from Baja California,Mexico

Five new entities ofEriogonum are described from Baja California and Baja California Sur, Mexico, including one species,E. preclarum, and four varieties of other species:E. fasciculatum var.emphereium,E. wrightii var.oresbium,E. elongatum var.areorivum, andE. grande var.testudinum. Three combinations are proposed:E. wrightii var.dentatum,E. elongatum var.vollmeri, andE. repens.     

New species of Spinuris (monogenea: monocotyladae) from Zapteryx exasperata (elasmobranchii: rhinobatidae) from Baja California Sur, Mexico.

Monocotylid monogeneans were collected from the gills of 2 Rhinobatos productus and 5 Zapteryx exasperata in Bahia Almeja, Baja California Sur, Mexico. All are parasitized by monocotylids of the genus Spinuris, 9 specimens of Spinuris lophosoma Doran on Rhinobatos productus (new record) and 27 specimens of Spinuris zapterygis n. sp. on Z. exasperata. This new species differs from the other species in the genus Spinuris by the number of dorsal haptoral sclerites, morphology of hooks, and male copulatory apparatus. The generic diagnosis of the genus Spinuris is revised.     

General characteristics of the diet of Trachinotus paitensis (Teleostei: Carangidae) from San Ignacio Lagoon, Baja California Sur, Mexico

The food habits of Trachinotus paitensis, in San Ignacio Lagoon B.C.S., Mexico, were investigated. We observed that T. paitensis is carnivorous, feeding mainly on benthic invertebrates (the gastropods Anachis spp., Bittium spp., and the crustacean larvae). We concluded that T. paitensis is an opportunist predator that impacts mainly on epibenthic invertebrates.     

Population dynamics of Megapitaria squalida (Bivalvia: Veneridae) at Magdalena Bay, Baja California Sur, Mexico

The population dynamics of an intertidal population of Megapitaria squalida was studied from September 2002 to February 2003 in Bahia Magdalena, Mexico. To obtain information about the artisanal and recreational fishery of M. squalida, local fishermen at different parts of the bay were interviewed. Clam densities were determined at one unexploited and two exploited sites along perpendicular transects from the shore line. Average clam density was 2.01+/-1.41 ind/m2, densities did not differ significantly between the three sampling sites. The length-total mass relation was Mtot = 0.0001*SL3.1644 (r2 = 0.9804, n = 92) and the length-tissue mass relation was Mtis = 0.0002*SL2.7144 (r2 = 0.945, n = 92). Von Bertalanffy-growth parameters were determined using marked individuals. Strong interindividual and also seasonal differences in growth were observed. Average annual values were: K = 0.655, Linfinity = 83 mm. Since M. squalida can reach a shell length of more than 135 mm in deeper waters, it is necessary to consider intertidal and subtidal populations separately. Average total mortality (Z) was 1.61 y(-1). No fishing mortality was calculated because total mortality Z at the unexploited control site was higher than Z at the exploited sites. It appears that M. squalida migrates into deeper water with increasing shell length, as average shell length increased at lower tidal levels and marked specimens showed a clear migration towards deeper waters. As yet no overexploitation could be found in the study area.     

Sex ratio and reproductive condition of four istiophorid billfishes in tropical regions of the eastern North Pacific Ocean: with special reference to striped marlin Kajikia audax (Philippi, 1887)

Sexual differences in the distribution pattern, sex ratio and the gonad condition of four istiophorid billfishes were investigated in three different tropical areas of the eastern North Pacific Ocean from September to November 2004. Sex ratios of striped marlin Kajikia audax were equal (female : male = 11 : 11) in the open‐ocean area (16–18°N, 118–134°W), biased to males (32 : 62) in the near‐continental area (13–16°N, 103–107°W), and biased to females (19 : 6) in the near‐equatorial area (5°N, 104–120°W). Sex ratios of sailfish Istiophorus platypterus in the near‐continental area and shortbill spearfish Tetrapturus angustirostris in the open‐ocean area were not biased from 1 : 1 (43 : 36, 11 : 13), and that of blue marlin Makaira nigricans in the near‐equatorial area was biased to females (14 : 1). Reproductively active females were found for striped marlin, sailfish and shortbill spearfish. Striped marlin showed a specific spawning area (the near‐continental area), and sexual dimorphism in its temporal distribution pattern, which was presumably related to reproduction. On the other hand, the limited distribution with evidence from spawning of sailfish and shortbill spearfish imply that these species complete their life history within limited areas.     

Feeding habits of the horn shark Heterodontus francisci (Girard, 1855) in the northwest of Baja California Sur,Mexico

The feeding habits of the horn shark, Heterodontus francisci (Girard, 1855), were examined in the area of Bahía Tortugas, Baja California Sur, Mexico in the spring, summer and fall of 2014. A total of 78 stomachs were collected, of which 46 (59%) contained food and 32 (41%) were empty. According to the percent Index of Relative Importance (%IRI), the most important prey categories in H. francisci's diet were anomurans (66%), cephalopods (7.2%), lobsters (4.7%), fishes (4.2%) and sea urchins (2.3%). The main prey were the anomuran Blepharipoda occidentalis (65.2%), the octopus Octopus bimaculatus (5.4%), the lobster Panulirus interruptus (4.7%) and the sea urchin Echinometra vanbrunti (2.6%). According to the Levin standardized Index (Bi), the trophic niche breadth in H. francisci is low (B_i = 0.21), making it a specialist predator. The species was classified as a tertiary consumer (trophic position = 4.06).     

Seasonal diet composition of Fundulus lima (Cyprinodontiformes: Fundulidae) in two oasis systems of Baja California Sur, Mexico

Fundulus lima inhabits river drainage systems and is threatened after the introduction of cichlids in the area. To support conservation programs, the spatial and temporal variation of the diet composition of this endangered killifish, was determined in two oasis systems of Baja California Sur, Mexico (San Ignacio and La Purisima river drainages), during rainy and dry seasons. F. lima was captured by using passive and active capture techniques. A total of 192 stomach contents of F. lima was analyzed. The contribution of each prey item in the diet composition was quantified by means of the indices of occurrence frequency (% OF), numerical (% N) and volume (% V) percentages. The relative importance of each prey item was determined according to the percentage of the Relative Importance Index (% RII). The similarity of the diet was calculated between hydrological basins (populations combined by basin), seasons (rainy versus dry months), sexes and size classes, by using Schoener's resource overlap index. We used two ecological indices to determine the type of feeding strategy exhibited by the fish: (1) niche breadth of Levins and (2) proportional similarity of Feisinger. Sand was the most abundant item in the stomach content of killifishes from both drainages (39% and 47%, respectively). Diet composition was similar for both drainages (74%) as well as among their respective size classes; however, it was different between sexes. In both drainages, F. lima predated mainly on diatom algae, dipterous and trichopteran larvae, and fish scales during the dry season; while it preferred dipterous larvae, filamentous algae and ostracods in the rainy season. A feeding strategy of opportunist type was exhibited by F. lima during the rainy season, changing to specialist type during the dry season. This information will be the basis for future investigations related to the conservation of this endangered species and its habitat.     

A new species of Sanicula L. (Umbelliferae/Apiaceae) endemic to Baja California, Mexico

A new species of the genusSanicula (sect.Sanicoria) endemic to the southern Sierra Juárez of Baja California, Mexico, is described and illustrated.Sanicula moranii resemblesS. deserticola andS. bipinnatifida, but has thicker basal leaves, with broader petioles and rachises, and shorter fruit prickles that are confined to the apical part of the mericarps. The taxonomic relationships of these species are discussed, along with aspects of their distribution and habitat.

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Resumen  Una neuva especie del géneroSanicula (secciónSanicoria) endémica de la Sierra Juárez de Baja California, México, es descrita e ilustrada.Sanicula moranii presenta similitud conS. deserticola yS. bipinnatifida, no obstante tiene gruesas hojas basales con pecíolos y raquis anchos, y espínulas del fruto más cortas que se distribuyen únicamente en la parte apical de los mericarpos. Además, se comentan las relaciones taxonómicas de las tres especies, así como algunos aspectos de sus distribuciones y hábitats.

     

Progebiophilus bruscai (Isopoda:Bopyridae) parasitizing the shrimp Upogebia dawsoni (Thalassinoidea:Upogebiidae), in Baja California Sur, Mexico)]

Parasitism of the isopod Progebiophilus bruscai Salazar-Vallejo & Leija-Tristán over the common mud shrimp, Upogebia dawsoni Williams, was analysed in the Ensenada and Bahia de La Paz, Baja California Sur, Mexico. Mud-shrimps were collected in three similar sites that differ in grain size and in the anthropogenic organic matter enrichment. Four-hundred-nine mud-shrimps were collected; the largest abundance was registered in the organically enriched site, but they were significantly smaller and more heavily parasited than the animals from the site lacking such organic enrichment. The size of the parasite is clearly dependent on the size of the mud-shrimp. This is the first study of the upogebiid-bopyris relationship in Mexico.     

First record of saddleback syndrome in wild parrotfish Sparisoma cretense (L., 1758) (Perciformes, Scaridae)

The saddleback syndrome is recorded for the first time in a wild fish population of the Mediterranean Sea. The deformed specimen belongs to Sparisoma cretense and presents the typical saddleback phenotype of missing spines in the dorsal fin.     

Seasonal variation of the agar quality and chemical composition of Gracilaria veleroae and Gracilaria vermiculophylla (Rhodophyceae,Gracilariaceae) from Baja California Sur,Mexico

Yield and physico‐chemical properties of agar from Gracilaria veleroae E.Y. Dawson and Gracilaria vermiculophylla (Ohmi) Papenfuss were studied and the chemical composition of the two seaweeds was determined. Samples were collected seasonally from summer 2003 to spring 2005. The agar yield did not vary significantly between seasons for both species. The lowest agar gel strength was obtained from G. veleroae (207.5 g cm^–2) in summer 2003 and the highest from G. vermiculophylla (793.1 g cm^–2) in winter 2004. Melting temperatures and hysteresis were higher in G. vermiculophylla, whereas gelling temperatures and 3,6‐anhydrogalactose content were higher for G. veleroae. Moisture, ash, crude fiber, and ether extract showed no significant seasonal variation for G. veleroae. The chemical composition of G. vermiculophylla showed significant seasonal variation. G. vermiculophylla possesses a better agar quality than G. veleroae and is a species that could be considered as a source of agar for commercial use.