Aldemaro Romero

It’s a wonderful hypogean life: a guide to the troglomorphic fishes of the world

There are at least 86 species of troglomorphic fishes belonging to 18 families. Some of those families are characterized by features that can be labeled as preadaptations to the hypogean life; others are not. The level of structural reduction in eye development and pigmentation is highly variable, even within some populations. Reduction in number and complexity of scales does occur but has yet to be fully documented. Reduction in the size and structure of the swim(gas)bladder may be another troglomorphic feature. There is considerable doubt on the taxonomic position of many species of troglomorphic fishes given that a number of them have been described solely on the basis of morphology while genetically they may be very closely correlated to genera different from those they have been assigned to. Geographically speaking there are no evident patterns since many of those species are not found in karstic areas but in phreatic waters. These fishes represent an excellent example of convergent evolution.

Scientists Prefer them Blind: The History of Hypogean Fish Research

The history of hypogean fish research has been strongly influenced by neo-Lamarckism (including orthogenesis) and typological thinking. Only in the last few decades neo-Darwinism has made any inroads in the research approach to this subject. The majority of the most distinguished and productive hypogean fish researchers have used their research subjects to confirm their own views on evolution rather than to use those subjects as a spring of knowledge to enrich mainstream biological thought. Of these views, I found that the most perversive of all is the notion of evolutionary ‘progress’ that has led many researchers to envision hypogean fishes as prime examples of ‘regressive’ evolution. I propose that the utilization of hypogean fishes for the study of convergent evolution should catapult these subjects of research into prime objects of evolutionary ideas.

Environmental history of marine mammal exploitation in Trinidad and Tobago, W.I. and its ecological impact.

Marine mammal exploitation has been documented for the Caribbean in recent times for only a handful of countries. Based on those studies a complex image of how that exploitation has taken place has begun to emerge. In order to fully understand whaling, dolphin fisheries, and manatee hunting, we still need to ascertain patterns of exploitation for many of the island-nations in that part of the world. We present a comprehensive analysis of marine mammal utilisation for Trinidad and Tobago. Trinidad and Tobago has been characterised by landbased whaling, organised during most of the nineteenth century by local elites. Dolphin fisheries have been rare and restricted to by-catches. Trinidad has the last remaining population of manatees among the eastern Caribbean islands, which is composed of a small number of individuals confined to a small swamp.

Behavior in an "intermediate" population of the subterranean-dwelling characid Astyanax fasciatus .

SynopsisA population of the characid Astyanax fasciatus was found living at the outflow of a subterranean source of water. Field observations revealed differences in behavior when compared with river populations. Affinity of this fish for the subterranean cavity was evidenced by behavior and distribution of individuals. Fish almost always carried bait into the subterranean cavity prior to feeding and also went into the cavity at night. Three factors may influence the affinity for the subterranean source of water: 1) protection against aerial predation, 2) the advantage to fishes of hovering in shade, 3) sheltering for reproduction. These observations suggest that cave colonization may take place actively rather than accidentaly, that behavioral changes may preceed morphological ones during initial stages of cave entry, and that behavioral adaptations may occur quite rapidly.

Responses to light in two blind cave fishes (Amblyopsis spelaea and Typhlichthys subterraneus) (Pisces: Amblyopsidae)

Explanations for the phenotypical features resulting from colonization of subterranean environments have always been a source of controversy. Although a great number of cave organisms are blind, they nevertheless display responses to light. The interpretation of this phototactic responsiveness in cave-dwelling animals may provide clues on the general issue of evolution of behavior in parallel with specialized structures. We studied the phototactic responses in two amblyopsid fishes of North America and found responses to light only in the species reported to have a functional pineal organ. Our findings are consistent with the hypotheses that (1) adaptation to the cave environment is a gradual process and (2) responsiveness to light in cave fishes may best be understood as a relict character, one that exists in an environment where it may never be expressed.

Replacement of the Troglomorphic population of Rhamdia quelen (Pisces: Pimelodidae) by an Epigean population of the same species in the Cumaca Cave, Trinidad, West Indies.

Abstract In 1926, Norman described the cave fish population in the Cumaca Cave of Trinidad, West Indies, as a new troglomorphic (blind/depigmented) genus and species, Caecorhamdia urichi, based on its reduction in eye size and pigmentation. Later studies indicated that this was just a cave population of the widely distributed epigean (surface, eyed/pigmented) catfish Rhamdia quelen. Beginning in the 1950s, a number of specimens were collected in the cave showing variability in eye size and pigmentation. In 2000 and 2001, we conducted field studies that included direct observation of individuals using infrared visual equipment (video cameras and night-vision goggles) and echo-sounders and also collected some individuals for behavioral research. We also examined all available specimens of the cave population that have been deposited in museums. Our results strongly suggest that the troglomorphic population has been completely replaced by the epigean one of the same species in as little as 50 years. We hypothesize that the most important reason for this replacement was the reinvasion of epigean individuals of R. quelen prompted by changes in precipitation regimes. Epigean individuals, because of their morphology, behavior, and ecological requirements, were well suited to outcompete troglomorphic individuals.

When Whales Became Mammals: The Scientific Journey of Cetaceans From Fish to Mammals in the History of Science

© 2012 Romero, licensee InTech. This is an open access chapter distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. When Whales Became Mammals: The Scientific Journey of Cetaceans From Fish to Mammals in the History of Science

In the Land of the Mermaid: How Culture, not Ecology, Influenced Marine Mammal Exploitation in the Southeastern Caribbean

Although some progress has been made toward a better understanding of marine mammal utilization in the Southeastern Caribbean, no comparative analysis has been carried out to see how such practices originated, developed, and finally impacted the marine mammal populations in that region. We conducted field and archival studies for Venezuela, Trinidad and Tobago, Grenada, Barbados, and St. Vincent and the Grenadines. We analyzed records of whaling, dolphin fisheries, and manatee exploitation for those countries, interviewed local fishers, and explored the remains of whaling stations in each area. Our results show that each of these countries developed a different pattern of whale and dolphin exploitation, but similar patterns of utilizing manatees. We conclude that these five neighboring countries, although sharing essentially the same marine mammal species, developed different exploitation practices in terms of species targeted, capture techniques, and time periods in which that exploitation took place, due to different cultural circumstances.

Whale Shark records and conservation status in Venezuela

Biodiversity welcomes this paper from Aldemaro Romero (an aquatic biologist with over 20 years of research experience, especially in the Caribbean area), A. Ignacio Agudo (a biologist who has been studying marine fauna off the coasts of Venezuela for the past 12 years), and Cristina Salazar (a biology and environmental studies graduate interested in the application of Geographic Information System [GIS] technology to conservation biology research). They have compiled the records of Whale Shark sightings seen in Venezuelan waters over a 51-year period. Although the sightings are relatively rare, only 20 in this time period, they appear to reflect a geographical distribution that is congruent with areas and periods of high productivity. There is also evidence that this species is being occasionally harpooned or accidentally netted. Based on this preliminary study and on the Precautionary Principle, the authors propose that the Whale Shark be classified as Vulnerable within Venezuelan waters. They also propose long-term population and behavioural studies to track individual animals to provide an accurate picture of the distribution and abundance of Rhincodon typus.

Threatened fishes of the world: Amblyopsis spelaea DeKay, 1842 (Amblyopsidae)

Common name: Northern cavefish (E). Conservation status: Vulnerable (World Conservation Monitoring Centre), State endangered species (Indiana Department of Natural Resources), species of special concern (Kentucky Nature Preserves Commission). Identification: This is one of the four species of troglobitic (cave, blind, and depigmented) fishes of the family Amblyopsidae. It is small, on average 84 mm SL, and range between 19 and 105 mm. Body depigmented with nonfunctional pigment cells. Looks pinkish due to the superficial blood vessels. Head length: 0.139–0.399; head width: 0.193–0.267; head depth: 0.150–0.236, D 9–11, A 8–11, P 9–11. Elongated body and head; head also depressed. Rudimentary eyes, hidden under the skin. Projecting jaw. Intermaxillaries and jaw covered by folds of skins or lips. Minute, slender, and slightly recurved teeth. Small cycloid scales, irregularly placed, and more or less embedded, so that the body appears naked. Lateral line present with external and internal neuromasts. Large branchial aperture with six branchiostegous rays on each side. Total gill rakers: 7. Total vertebrae: 29–30. Differs from Amblyopsis rosae in the number of dorsal, anal, and caudal rays, the presence of pelvic fin and other meristic characteristics. Distribution: In about 2 500 caves in Kentucky and about 1 800 caves in southern Indiana. Its distribution may be limited by competition with another amblyopsid cavefish, Typhlichthys subterraneus.Abundance: unknown for its entire range. Habitat and ecology: Found only in caves and subterranean passages of well-developed karst terrain whose water comes from the precipitation diverted underground through sinkholes and sinking streams. It is most often found in caves with uniform silt-sand substrates. It is a top predator. Reproduction: It has a well-defined year cycle. Breeding occurs during high water from February to April. The females carry the eggs in their gill cavities until hatching and carry the young until they lose their yolksacs, a total period of 4–5 months. Free swimming young appear in late summer and early fall. Low reproduction rate. Threats: This species occupies a highly restricted habitat. Vulnerable to any disturbance in the water such as ground water pollution, sedimentation, runoff, impoundments, quarrying, and overcollecting. Conservation action: It is not protected by U.S. federal law, but Indiana and Kentucky state agencies have taken some measures for its conservation. Conservation recommendations: Eliminate or reduce destructive land use practices, additional sediment and runoff control for construction projects, eliminate use of agrochemicals in critical watersheds, eliminate mineral development activities, eliminate water impoundment projects, limit access to sites. Remarks: It was first described from the streams of Mammoth cave by DeKay in 1842. Despite the lack of eyes it does respond to light by moving away from it (scotophilia).