Bay Of Panama Research Articles

Identification of weakfishCynoscion(Gill) in the Bay of Panama with RFLP markers

A molecular approach, polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP), was developed to identify the planktonic larvae of Cynoscion species. Species-specific mitochondrial DNA markers were developed using three restriction endonucleases (DdeI, HaeIII and HinfI). These markers permitted the accurate discrimination of the five Cynoscion species in the Bay of Panama.

Hydromedusa blooms and upwelling events in the Bay of Panama, Tropical East Pacific

Seasonal upwelling events dominate the coastal areas of some regions of the Tropical East Pacific. The effects of upwelling on gelatinous zooplankton are largely unknown and undocumented for this or any region, although upwelling is known to shape phytoplankton dynamics. Small hydromedusae, the most widespread and diverse representatives of gelatinous plankton, are often neglected in plankton ecology as they are inconspicuous and escape direct observation. Their occurrence is seasonal and standard plankton sampling techniques easily overlook their blooms. In order to investigate whether upwelling affects hydromedusae dynamics, we monitored their abundance and diversity in the Bay of Panama, a region on the Pacific Coast of Panama characterized by seasonal upwelling events. Our results show that, although the number of species is relatively constant throughout the year, hydromedusa abundance in the Bay of Panama can be up to two orders of magnitude higher during upwelling than non-upwelling conditions. The difference in the numbers of hydromedusae between the two seasons is mostly due to temporally short medusa blooms that occur only during the upwelling season. Our results point to a link between hydromedusa blooms and upwelling events, and the increased productivity associated with them. The results are consistent with a scenario in which upwelling events act on the benthic colonies thus inducing medusa production.

Vertical zonation of rocky intertidal organisms in a seasonal upwelling area (Eastern Tropical Pacific), Costa Rica

The intertidal rocky shore of Bahia Salinas (seasonal upwelling area), northern Pacific coast of Costa Rica, was studied to determine the vertical zonation of algae and invertebrates. In two sheltered and two exposed sites the communities were sampled twice, once during the upwelling (April) and again during the nonupwelling season (October). At each site five strata were sampled with 25x25cm quadrats. Each stratum had five quadrats and digital photographs of each quadrat were taken. Digital image analysis was used to estimate the percent cover of sessile species and abundance of mobile fauna. A typical vertical zonation was found using Principal Component Analysis (PCA) biplot and Multiple Discriminant Analysis (MDA). The analysis of similarities (ANOSIM) detected a seasonal change in the biological composition of the inferior strata. This change in the percent cover of the algal assemblage and their herbivores were related to the seasonal upwelling. Sessile invertebrates had a constant percent cover between April and October, but the difference between exposed and sheltered sites was significant. Invertebrates showed a patchy structure in sheltered sites while in exposed sites organisms formed horizontal bands. Interactions between species indicated that predation and space monopolization were possible causes of lower cover of barnacles in sheltered sites and lower abundance of mollusks in the exposed area. Regional difference of intensity in the upwelling event and larval recruitment may explain the high cover of sessile invertebrates of Bahia Salinas in comparison to the Bay of Panama, another seasonal upwelling system. Rev. Biol. Trop. 56 (Suppl. 4): 91-104. Epub 2009 June 30.

Trace element profiles as unique identifiers of western sandpiper (Calidris mauri) populations

Understanding the ecology and evolution of migratory animals requires information on how populations are geographically linked between periods of the annual cycle. To examine whether trace elements could be used to track migratory birds, we analyzed concentrations of 42 trace elements in feathers of western sandpipers ( Calidris mauri (Cabanis, 1857)) that were grown at five different wintering sites ranging from San Francisco Bay (USA) to the Bay of Panama. Linear discriminant analysis of 15 elements correctly classified all 26 individuals to their wintering sites, including two sites that were separated by less than 3 km. A randomization procedure confirmed the robustness of these findings. Our analysis suggests that trace elements can be used to assign individuals to specific sites of origin. Although we did not sample feathers from all wintering areas, the regions our sites represented comprised a significant percentage of the global population. However, since trace element profiles appear to be highly specific to geographic sites, we suggest that this technique is best suited for cases where samples can be obtained from the majority of populations throughout a species range. Thus, under certain circumstances, trace element profiles may provide the potential to identify populations with a high degree of spatial accuracy.

Echinoids of the Pacific waters of Panama: status of knowledge and new records.

This paper is primarily intended as a guide to researchers who wish to know what echinoid species are available in the Bay of Panama and in the Gulf of Chiriqui, how to recognize them, and what has been published about them up to 2004. Fifty seven species of echinoids have been reported in the literature as occurring in the Pacific waters of Panama, of which I have collected and examined 31, including two species, Caenopedina dìomedìae and Meoma frangibilis, that have hitherto only been mentioned in the literature from single type specimens. For the 31 species I was able to examine, I list the localities in which they were found, my impression as to their relative abundance, the characters that distinguish them, and what is known about their biology and evolution. Not surprisingly, most available information concerns abundant shallow water species, while little is known about deep water, rare, or infaunal species.

Mitochondrial Perspective on the Phylogenetic Relationships of the Parula Wood-warblers

Studies of intraspecific genetic variation in Neotropical resident birds have frequently revealed a high degree of phylogeographic differentiation (e.g. Capparella 1988, Hackett and Rosenberg 1990, Peterson et al. 1992, Bates and Zink 1994, Hackett 1996). That trend suggests tropical bird species are particularly likely to be subdivided geographically and that their constituent lineages tend to be evolutionarily old. Only a few counterexamples have been reported in which molecular surveys of Neotropical avian species did not reveal phylogeographic structure. Brawn et al. (1996) found no differences in mtDNA RFLP haplotypes between populations of three passerine species on the Perlas Islands in the Bay of Panama and conspecific populations on the nearby mainland. However, the geographic distances (<100 km) and putative period of genetic isolation (<10,000 years) in that system were both short. Gutierrez (1994) found similarly low mtDNA divergence in Oilbirds (Steatornis caripensis) from colonies 400 km apart in northern Venezuela. On a broader geographic scale, Brumfield and Capparella (1996) observed considerable protein divergence between Central and South American House Wrens (Troglodytes aedon), but found little differentiation among locations along a 7,000 km transect from Panama to Tierra del Fuego. Here we explore the magnitude of mtDNA differentiation among geographically distant populations of the Tropical Parula (Parula pitiayumi), and we use mtDNA sequences to explore the relationship of R pitiayumi to the three other species currently placed in Parula (AOU 1998). Parula pitiayumi has a breeding distribution that extends from Northern Mexico south through much of South America and has been divided into 14 subspecies (Lowery and Monroe 1968). Based on its broad geographic distribution and high phenotypic diversity, our a priori expectation was that R pitiayumi would display evidence of

Arthropod-frog connection: decahydroquinoline and pyrrolizidine alkaloids common to microsympatric myrmicine ants and dendrobatid frogs.

Neotropical poison frogs (Dendrobatidae) contain a wide variety of lipophilic alkaloids, apparently accumulated unchanged into skin glands from dietary sources. Panamanian poison frogs (Dendrobates auratus) raised in a large, screened, outdoor cage and provided for six months with leaf-litter from the frog's natural habitat, accumulated a variety of alkaloids into the skin. These included two isomers of the ant pyrrolizidine 251K; two isomers of the 3,5-disubstituted indolizidine 195B; an alkaloid known to occur in myrmicine ants; another such indolizidine, 211E; two pyrrolidines, 197B and 223N, the former known to occur in myrmicine ants; two tricyclics, 193C and 219I, the former known to occur as precoccinelline in coccinellid beetles; and three spiropyrrolizidines, 222, 236, and 252A, representatives of an alkaloid class known to occur in millipedes. The alkaloids 211E, 197B, and 223N appear likely to derive in part from ants that entered the screened cage. In addition, the frog skin extracts contained trace amounts of four alkaloids, 205D, 207H, 219H, and 231H, of unknown structures and source. Wild-caught frogs from the leaf-litter site contained nearly 40 alkaloids, including most of the above alkaloids. Pumiliotoxins and histrionicotoxins were major alkaloids in wild-caught frogs, but were absent in captive-raised frogs. Ants microsympatric with the poison frog at the leaf-litter site and at an island site nearby in the Bay of Panama were examined for alkaloids. The decahydroquinoline (−)-cis-195A and two isomers of the pyrrolizidine 251K were found to be shared by microsympatric myrmicine ants and poison frogs. The proportions of the two isomers of 251K were the same in ant and frog.

The Usefulness of Bivalve Stable Isotope Profiles as Environmental Indicators: Data from the Eastern Pacific Ocean and the Southern Caribbean Sea

We constructed stable isotope profiles for 16 Recent venerid bivalve shells from four environmental regions in the eastern tropical Pacific and the southwestern Caribbean. The environments sampled were: 1) the Gulf of Chiriqui, a nonupwelling region in the eastern Pacific; 2) Panama Bay, an upwelling region in the eastern Pacific; 3) the Caribbean non-upwelling region of northern Panama and northwestern Colombia west of Cartegena; and 4) the Caribbean upwelling region of northern Colombia east of Cartagena and the northern Gulf of Venezuela. The four environments are generally well-characterized by the shell profiles. In particular, the 6180 range is greatest in upwelling environments, and, to a lesser extent, is greater in the eastern Pacific than in the Caribbean.

The efficacy of guayule resin as a pesticide

Researchers from the United States are evaluating the nonrubber-producing extract (resin) of the guayule bush ( Parthenium argentatum Gray) as a potential wood protectant against marine and terrestrial wood-destroying organisms in Panama. Wood treated with guayule resin was not attacked, or only lightly attacked, by limnorians (crustacean borers) after 45 months in Limon Bay. After 19 months in the Bay of Panama, treated wood was undamaged by teredinids but heavily damaged by pholads; both are molluscan borers. Treated wood was not attacked by termites of the genus Coptotermes during 33 months of exposure in the Panamanian rain forest. Termites of the genus Heterotermes had not attacked wood treated with guayule resin after 45 months in the Panamanian rain forest. A 20-week laboratory evaluation of guayule resin for efficacy against brown-rot ( Gleophyllum trabeum, Antrodia carbonica, Formitopsis cajanderi, Lentinus ponderosa) and white-rot ( Dichomitus squalens, Trametes versicolor, Ganodermas sp) fungi was performed. Statistical analysis revealed a significant inhibition of decay of the treated wood by these organisms. A 12-week laboratory evaluation of guayule resin for efficacy against soft-rot fungi was also conducted. None of the treated wood was damaged by soft-rot fungi.

Recruitment Regulates Demographic Variation in a Tropical Intertidal Barnacle

I studied populations of the barnacle Chthamalus fissus on the central Pacific coast of Costa Rica to determine the relative importance of pre— and post—settlement processes in determining patterns of distribution and abundance. Populations were studied at 10 sites representing five different microhabitats on one shore. Sites were censused photographically from 1983 to 1985 at 1—3 mo intervals, yielding data on recruitment, growth, and mortality. Mortality after settlement (=after day 1) was density independent for at least 90 d, so recruitment reflected settlement. Abundance appeared limited by sparse recruitment since considerable bare space was available at most sites during much of the study. Intraspecific competition (preemptive and adult—adult) was weak, except after occasional peaks of dense recruitment. Interspecific interactions were also weak, except for localized, intense predation by the thaidid gastropod Acanthina brevidentata near cracks and crevices, and sporadic competition with the small mussel Brachidontes semilaevis. In large part, demography of C. fissus was regulated by events in the water column affecting settlement and subsequent recruitment. Similar communities are found on rocky shores in the Bay of Panama, in central Costa Rica, and in the northern Gulf of California. Recruitment of Chthamalus spp. is very sparse in the Bay of Panama, sparse with occasional peaks in central Costa Rica, and consistently dense in the northern Gulf of California. Post—settlement processes involving Chthamalus spp. (competition and predation) appear strong and pervasive only in the northern Gulf of California. Abundance of Chthamalus fissus in Central America is regulated by events in the water column that determine the number of cyprids arriving to the substratum, an example of supply—side ecology.

Diel and lunar patterns of reproduction in the Caribbean and Pacific sergeant major damselfishes Abudefduf saxatilis and A. troschelii

Diel and lunar reproductive patterns of the Caribbean and Pacific sergeant major damselfishes Abudefduf saxatilis and A. troschelii respectively, were studied i the San Blas and Northern Perls Islands of Panama in 1981 and 1982. These are sister-species that have diverged since the uplift of the isthmus of Panama. Caribbean A. saxatilis females typically complete spawning in the nests of males earlier in the morning than do Pacific A. troschelii females. Spawning is rarely observed during the afternoon. Hatching occurs four or five days after spawning in the Caribbean species, and after four days in the Pacific species. In both, fry hatch during the hour following sunset. There also are differences in lunar patterns of spawning between the two species. The Caribbean A. saxatilis spawns throughout the month, exhibiting no lunar periodicity. In the Pacific A. troschelii spawns within nine days on either side of new moon. During the wet season, reproductive activity at a site spans three or four days, but is extended to eight or more days during dry season upwelling in the Bay of Panama. Thus, reproductive synchrony is much greater within than between colonies of the Pacific sergeant major, particularly in the wet season. Reproductive synchrony in the Pacific sergeant major might be beneficial because fry hatching at dusk encounter favorable tides for transport away from reef-based predators around new moon, or because reproductive synchrony reduces the risk of predation on unhatched embryos in nests guarded by males. Tidal amplitude and the rate of predation on embryos in nests are greater in the Pacific.

Natural history and social organization of the semiterrestrial grapsid crab Pachygrapsus transversus (Gibbes)

Pachygrapsus transversus (Gibbes) was studied in the intertidal zone of the Bay of Panama. Individuals are active at all low tides as soon as their habitat is exposed. Crabs on large rocks occupy holes and crevices that provide food, refuge from predators, and relief from thermal stress. Males and females move daily from the refuge rocks to flat smooth rocks where they graze on algae. P. transversus is omnivorous, feeding on algae, porcelain crabs, fish and conspecifics. Predators on the crabs include raccoons, fish, and birds. Behavioral displays of P. transversus are described. Males maintain non-exclusive core areas on the refuge rocks, with larger males defending larger areas. A typical area contains a single dominant male, zero to five subordinate males, three to eight mature females, and seven to 25 non-interacting juveniles. All observed matings occurred on these areas; dominant males copulated in 83–88% of the matings. We suggest that predation and heat stress are the selection pressures favoring use of holes as refuges. The fact that some holes are occupied by females may have led to the evolution of male dominance and defense of these areas.

Experimental separation of effects of consumers on sessile prey in the low zone of a rocky shore in the Bay of Panama: direct and indirect consequences of food web complexity

The effects of predation by a diverse assemblage of consumers on community structure of sessile prey was evaluated in the low rocky intertidal zone at Taboguilla Island in the Bay of Panama. Four functional groups of consumers were defined: (1) large fishes, (2) small fishes and crabs, (3) herbivorous molluscs, and (4) predaceous gastropods, (l) and (2) included fast-moving consumers and (3) and (4) included slow-moving consumers. Experimental treatments were: no consumers deleted (all groups present), most combinations of deletions of single groups (i.e., one group absent, three present), pairs of groups deleted (two absent, two present), trios of groups deleted (three absent, one present), and the entire consumer assemblage deleted (all groups absent). Changes in abundance (percent cover) of crustose algae, solitary sessile invertebrates, foliose algae, and colonial sessile invertebrates were quantified periodically in 2–4 plots of each treatment from February 1977 to January 1980 after the initiation of the experiment in January 1977. Space on this shore is normally dominated by crustose algae; foliose algae, solitary sessile invertebrates, and colonial sessile invertebrates are all rare. After deletion of all consumers, ephemeral green algae increased from 0 to nearly 70% cover. Thereafter, a succession of spatial dominants occurred, with peak abundances as follows: the foliose coralline alga Jania spp. by July 1977, the barnacle Balanus inexpectatus by April 1978, and the rock oyster Chama echinata by January 1980. Although no longer occupying primary rock space, Jania persisted as a dominant or co-dominant turf species (with the brown alga Giffordia mitchelliae and/or the hydrozoan Abietinaria sp.) by colonizing shells of sessile animals as they became abundant instead of the rock surface. Multivariate analysis variance (MANOVA) indicated that the effect of each group was as follows. Molluscan herbivores grazed foliose algae down to the grazer-resistant, but competitively inferior algal crusts, altered the relative abundances of the crusts, and inhibited recruitment of sessile invertebrates. Predaceous gastropods reduced the abundance of solitary sessile animals. Small fishes and crabs, and large fishes reduced the cover of solitary and colonial sessile animals and foliose algae, although they were incapable of grazing the foliose algae down to the rock surface. Many of the effects of each consumer group on prey groups or species were indirect; some effects were positive and some were negative. The variety of these indirect effects was due to both consumer-prey interactions among the consumers, and competitive or commensalistic interactions among the sessile prey. Comparison of the sum of the effects of each of the single consumer groups (i.e., the sum of the effect observed in treatments with one group absent, three present) with the total effects of all consumers (i.e., the effect observed in the treatment with all groups absent) indicates that a “keystone” consumer was not present in this community. Rather, the impacts of the consumer groups were similar but, due to dietary overlap and compensatory changes among the consumers, not readily detected in deletions of single consumer groups. The normally observed dominance of space by crustose algae is thus maintained by persistent, intense predation by a diverse assemblage of consumers on potentially dominant sessile animals and foliose algae. The large difference in structure between this and temperate intertidal communities seems due to differences in degree, not kind of ecological processes which produce the structure.

Fish predation on gastropods on the Pacific Coast of Costa Rica

The intensity of fish predation was measured by comparing loss of gastropod shells at four intertidal shores on the Pacific Coast of Costa Rica. Fish had little effect on shell losses of gastropods although some shell crushing occurred. Fish predation intensity in central Costa Rica was variable in space and time and was lower than in the Bay of Panama. Rate of loss of gastropods in Costa Rica was as low as that documented for temperate regions, suggesting that variation among latitudes (temperate vs. tropical) is no higher than variation at similar latitudes (Panama vs. Costa Rica). Local variation within each region should be considered when temperate-tropical comparisons are made.

Structure, persistence, and role of consumers in a tropical rocky intertidal community (Taboguilla Island, Bay of Panama)

The physical environment and patterns of distribution and abundance of macroalgae, sessile and mobile animals are described for the littoral zone of Taboguilla Island, Bay of Panama. The substratum is basaltic and heterogeneous in both texture and topography. Some physical factors vary seasonally. During the wet season, (May to mid-December) rain is frequently heavy, daily air temperatures range from 24 to 31.5°C, surface sea-water temperatures range from 26 to 28°C, and wind is usually low but variable in speed and direction. During the dry season (mid-December through April), rain is infrequent, daily air temperatures range from 22 to 32°C, surface sea-water temperatures range from 18 to 27°C, wind ranges from northwesterly to northeasterly and can reach 30 knots. Water clarity is usually poor throughout the year. Taboguilla shores appear barren throughout the year because benthic animals and erect macroalgae are rare on exposed rock surfaces. In the high zone most surfaces are bare (91.5 to 98.1%), with small barnacles Chthamalus fissus (Darwin), Euraphia imperatrix (Pilsbry) the dominant space-occupants. In mid and low zones, encrusting algae dominate space (25.9 to 92.5% cover) and sessile animals are scarce (< 1 to 9.8% cover). Maximum cover (7.0%) of erect algae occurs in the low zone. The plants are short, < 5 cm tall. Consumers (e.g., limpets, predaceous gastropods, crabs, chitons, fishes) are diverse and abundant in all zones. Both prey and consumer species composition and abundances change from high to low zones. Densities tend to vary more in the high, and less in lower zones. The large herbivorous crab Grapsus grapsus (L.) is usually most abundant at higher intertidal levels. In contrast, fishes are probably effectively denser in lower than in higher zones, at least at high tide, although many range throughout the intertidal as well as the subtidal zones. Both species richness ( S) and diversity ( H′) increase with decreasing tidal level. Despite the seasonal changes in the physical environment, seasonal changes in community structure are small or lacking. Annual changes are sometimes larger, but still small in comparison to temperate regions. That crustose algae dominate this otherwise relatively barren shoreline seems due to: (1) intense, consistent grazing and predation by a diverse assemblage of vertebrate and invertebrate consumers on the upright algae and sessile animals, (2) desiccation, possibly ultraviolet and heat stress, especially at higher tidal levels, and (3) possible inhibition of settlement by crustose algae.

Timing of Brown Pelican Nesting on Taboga Island in Relation to Upwelling in the Bay of Panama

Timing of Brown Pelican Nesting on Taboga Island in Relation to Upwelling in the Bay of Panama

Structure, persistence, and role of consumers in a tropical rocky intertidal community (Taboguilla Island, Bay of Panama) : Lubchenco, Jane et al., 1984. J. expl mar. Biol. Ecol., 78(1/2):23–73

Structure, persistence, and role of consumers in a tropical rocky intertidal community (Taboguilla Island, Bay of Panama) : Lubchenco, Jane et al., 1984. J. expl mar. Biol. Ecol., 78(1/2):23–73

Use of artificial holes in studying community development in cryptic marine habitats in a tropical rocky intertidal region

Previous studies on the rocky intertidal shores of the Bay of Panama indicate that for many sessile and mobile organisms holes and crevices are important refuges from consumers. To study the dynamics of these hole-dwelling species assemblages, we devised a method allowing repetitive, non-destructive sampling and species manipulations in artificial holes. These are fiberglass sleeves with flanges at the outer edge that are inserted into receptacles made of quick-setting concrete. Predator and herbivore manipulations include: fences excluding slow-moving benthic consumers, bars across hole mouths restricting entry of large fishes and homogeneous (shelterless) surfaces created around a treatment decreasing abundance of small crabs. This design has withstood the rigors of two wet seasons in Panama. Results from two sites in Panama indicate that colonization occurs rapidly (6–7 months) in holes established in mid dry season. Encrusting fleshy algae (Ralfsia sp.) and ephemeral green algae (Cladophora spp.) colonize first and are succeeded by encrusting species of coralline algae, bryozoans and colonial tunicates and by erect fleshy red algae. Where consumers are present, encrusting corallines predominate; without consumers, bryozoans, tunicates and erect algae are more abundant. Zonation patterns develop within the holes, with the desiccation/heattolerant Ralfsia sp. dominating at the outer edges. With increasing deph, encrusting coralline algae, bryozoans and colonial tunicates reach their respective peak abundances. In contrast to the high variability observed among naturally occurring holes, replicates of each treatment tend to be similar. Between-treatment and between-site comparisons are less so. The naturally-occurring high level of small-scale patchiness is thus presumably due to variation in recruitment and in the local (microspatial) consumer regime. Substratum heterogeneity is therefore directly and indirectly important in maintaining a high local diversity in this community. As in other studies, consumers or disturbances are key factors in regulating patterns of community structure. More experiments of longer duration are necessary to ascertain the relative importances of consumers/disturbance and competition in controlling such assemblages.

A new species of Phestilla; the first record of a corallivorous aeolid nudibranch from tropical America

A new species of aeolid nudibranch mollusc of the genus Phestilla (Tergipedidae) is described from the Bay of Panama, on the Pacific coast of tropical America. It feeds on the scleractinian coral Porites lobata and preliminary histological evidence suggests that it may have a symbiosis with zooxanthellac it removes from the Porites tissue.

Shell utilization, predation pressure, and thermal stress in panamanian hermit crabs: An interoceanic comparison

Shell preference patterns of two common hermit crabs from hard bottom reef flats on the Caribbean coast of Panama are examined in relation to the predation pressures and physical stresses of their habitat. Clibanarius antillensis Stimpson lives in the high intertidal habitat and minimizes exposure to predators by seeking refuge during high tides. It prefers high-spired shells which maximize protection from thermal stress. Calcinus tibicen Herbst avoids tidal emersion and prefers low-spired shells which enhance resistance to the predators common on Caribbean reef flats. The results are compared with similar results from the tropical eastern Pacific Bay of Panama. Shell-crushing predation on Caribbean hermit crabs is suggested to differ quantitatively and qualitatively from predation on hermit crabs in the Bay of Panama. Predation on hermit crabs in the Bay of Panama is more intense and effects larger individuals than predation on Caribbean reef flat hermit crabs. In addition, shell-crushing predation on hermit crabs in the Bay of Panama is primarily from teleost fish predators ( Diodon spp.), while predation on Caribbean hermit crabs is primarily by bottom-dwelling crustaceans. Differences in predation pressures and tidal regimes between the Caribbean and Pacific coasts of Panama are reflected in the shell preferences and behavior of hermit crabs from the two areas.