Hawaiian biogeography and the islands' freshwater fish fauna

Aim This paper describes known patterns in the distributions and relationships of Hawaiian freshwater fishes, and compares these patterns with those exhibited by Hawaii's terrestrial biota. Location The study is based in Hawaii, and seeks patterns across the tropical and subtropical Indo‐west Pacific. Methods The study is based primarily on literature analysis. Results The Hawaiian freshwater fish fauna comprises five species of goby in five different genera (Gobiidae). Four species are Hawaiian endemics, the fifth shared with islands in the western tropical Pacific Ocean. All genera are represented widely across the Indo‐west Pacific. All five species are present on all of the major Hawaiian islands. All five species are amphidromous – their larval and early juvenile life being spent in the sea. Although there has been some local phyletic evolution to produce Hawaiian endemics, there has been no local radiation to produce single‐island endemics across the archipelago. Nor is there evidence for genetic structuring among populations in the various islands. Main conclusions In this regard, the freshwater fish fauna of Hawaii differs from the well‐known patterns of local evolution and radiation in Hawaiian Island terrestrial taxa. Amphidromy probably explains the biogeographical idiosyncrasies of the fish fauna – dispersal through the sea initially brought the fish species to Hawaii, and gene flow among populations, across the archipelago, has hitherto inhibited the evolution of local island endemics, apparently even retarding genetic structuring on individual islands.     

Comparison of the parasitic fauna of Aplocheilus panchax and A. melastigma

The metazoan parasite fauna of two species of freshwater fishes Aplocheilus panchax and A. melastigma collected from a stream at Waltair is compared; 17 parasite species were found. Aplocheilus panchax served as a host to 13 parasite species and A. melastigma to 10 parasite species. Of the 17 parasites collected, 12 were larval helminths to which the fishes act as intermediate and paratenic hosts. This has been attributed to the interaction between terrestrial birds, mammals and fishes in determining the parasite fauna in the biocoenosis. The parasite fauna of these fishes is divided into typical and less typical according to their frequencies. Among less typical there are peripheral division parasites which are abundant in other fishes in the stream. Only six parasite species occurred in both A. panchax and A. melastigma and both fish shared most of their parasite fauna with other fishes. Differences in the parasite fauna of these fishes are attributed to the morphological, behavioural or ecological features of these fishes.     

Molecular phylogeny and biogeography of the endemic Hawaiian Succineidae (Gastropoda: Pulmonata)

The endemic Hawaiian Succineidae represent an important component of the exceptionally diverse land snail fauna of the Hawaiian Islands, yet they remain largely unstudied. We employed 663-bp fragments of the cytochrome oxidase I (COI) mitochondrial gene to investigate the evolution and biogeography of 13 Hawaiian succineid land snail species, six succineid species from other Pacific islands and Japan, and various outgroup taxa. Results suggest that: (1) species from the island of Hawaii are paraphyletic with species from Tahiti, and this clade may have had a Japanese (or eastern Asian) origin; (2) species from five of the remaining main Hawaiian islands form a monophyletic group, and the progression rule, which states that species from older islands are basal to those from younger islands, is partially supported; no geographic origin could be inferred for this clade; (3) succineids from Samoa are basal to all other succineids sampled (maximum likelihood) or unresolved with respect to the other succineid clades (maximum parsimony); (4) the genera Succinea and Catinella are polyphyletic. These results, while preliminary, represent the first attempt to reconstruct the phylogenetic pattern for this important component of the endemic Hawaiian fauna.     

Insular Freshwater Fish Faunas of Micronesia: Patterns of Species Richness and Similarity

Freshwater fishes are an important but relatively little known component of the highly diverse fish fauna of Micronesia. Localities supporting communities of freshwater fishes include large high islands, with considerable habitat complexity, and smaller low islands, such as atolls and raised coral islands, with limited freshwater habitat. Both types of islands may support species with adult life history styles that are (a) amphidromous and catadromous, (b) euryhaline (often estuarine), or (c) marine species which enter freshwater from time to time. We compared patterns of species richness and similarity between Micronesian localities for amphidromous and catadromous, euryhaline and marine species (ACEM) pooled, and for amphidromous and catadromous species (ACFW). Species richness of both ACEM and ACFW fishes was greatest on larger high islands compared to smaller high and all low islands. Cluster analysis of similarity indices for ACEM species between localities revealed two faunal components: high islands and low islands. High islands were further partitioned into a Caroline Islands cluster and a separate Mariana Islands cluster. Cluster analysis of ACFW species was more complex. One cluster consisted of a low island and a small high island, both in the Carolines chain and with limited freshwater habitat. The second cluster was partitioned into high islands and low islands that reflected influences of both size and geographical location.     

Prehistoric fisheries in the Caribbean

We studied faunal remains from archaeological sites on five Caribbean islands, each with an early (1,850-1,280 years B.P.) and late (1,415-560 years B.P.) occupation. On each of these islands (Puerto Rico, St. Thomas, St. Martin, Saba, and Nevis), the mean size of reef fishes in the faunal remains declined from the early to the late occupation. The large samples from sites on St. Thomas and Nevis allowed examination of the size distribution of individual taxa. Samples of obligate reef fishes (Scaridae, Acanthuridae, Lutjanidae, and Serranidae) showed large reductions in size between the early and late occupations. Samples of facultative reef fishes (Carangidae and Clupeidae) showed little change in size frequency distribution. The percentage of estimated reef fish biomass in the total aquatic faunal record sharply declined in the samples from four of the islands, while on Nevis there was a slight increase. The mean trophic level of reef fishes declined from the early to the late occupations on each island. Together these patterns suggest that populations of reef fishes adjacent to occupation sites on these islands were heavily exploited in prehistoric times. Such exploitation resulted in shifts in size structure and species composition among the reef fish fauna. On some islands the decline in reef fish resources corresponded with a shift towards greater exploitation of pelagic species.     

Zoogeography of the shorefish fauna of Clipperton Atoll

One hundred and fifteen species of fishes (14 oceanic, plus 101 shore and nearshore species) are known from Clipperton Island, a small, remote coral atoll in the tropical eastern Pacific (TEP). This fish fauna includes only 14% of the region's shallow-water species, and also is depauperate relative to the fish faunas of other isolated tropical islands. The island's isolation, small size, reduced habitat diversity, and oceanic environment contribute to this paucity of species.Fifty-two species at Clipperton can be identified as TEP; these include 37 widespread species, six species shared only with the Revillagigedo Islands [the nearest (950 km) offshore shoals], and eight endemic to Clipperton. Endemics species apparently have a mix of west and east Pacific origins. Sixty-three species are transpacific; they include three new records (of Naso surgeonfishes) that maybe vagrants recruited > 4,000 km from Oceania.Clipperton is situated at the juncture between the TEP and Oceania. Its fish fauna contains about equal numbers of TEP and transpacific species. This faunal structure reflects the relative influence of surface currents from Oceania and the TEP. Although most of Clipperton's transpacific shorefishes are widespread in eastern Oceania, the Clipperton fauna has specific affinities to the fauna of the Line Islands, which are located within the main eastbound current from Oceania. Clipperton may therefore be a major stepping stone for dispersal between Oceania and the remainder of the TEP. About 50% of the non-oceanic, tropical transpacific fishes occur there, and at least 75 % of those species apparently have resident populations at the island.     

Stepping stone speciation in Hawaii’s flycatchers: molecular divergence supports new island endemics within the elepaio

The elepaio (Chasiempis sandwichensis) is a monarch flycatcher endemic to the Hawaiian Islands of Kauai, Oahu, and Hawaii. Elepaio vary in morphology among and within islands, and five subspecies are currently recognized. We investigated phylogeography of elepaio using mitochondrial (ND2) and nuclear (LDH) markers and population structure within Hawaii using ND2 and microsatellites. Phylogenetic analyses revealed elepaio on each island formed reciprocally monophyletic groups, with Kauai ancestral to other elepaio. Sequence divergence in ND2 among islands (3.02–2.21%) was similar to that in other avian sibling species. Estimation of divergence times using relaxed molecular clock models indicated elepaio colonized Kauai 2.33 million years ago (95% CI 0.92–3.87 myr), Oahu 0.69 (0.29–1.19) myr ago, and Hawaii 0.49 (0.21–0.84) myr ago. LDH showed less variation than ND2 and was not phylogenetically informative. Analysis of molecular variance within Hawaii showed structure at ND2 (fixation index = 0.31), but microsatellites showed no population structure. Genetic, morphological, and behavioral evidence supports splitting elepaio into three species, one on each island, but does not support recognition of subspecies within Hawaii or other islands. Morphological variation in elepaio has evolved at small geographic scales within islands due to short dispersal distances and steep climatic gradients. Divergence has been limited by lack of dispersal barriers in the extensive forest that once covered each island, but anthropogenic habitat fragmentation and declines in elepaio population size are likely to decrease gene flow and accelerate differentiation, especially on Oahu.     

Invasive Temperate Species are a Threat to Tropical Island Biodiversity

To protect the remaining biodiversity on tropical islands it is important to predict the elevational ranges of non-native species. We evaluated two hypotheses by examining land snail faunas on the eastern (windward) side of the island of Hawaii: (1) the latitude of a species' native region can be used to predict its potential elevational range and (2) non-native temperate species, which experience greater climatic fluctuations in their native range, are more likely to become established at higher elevations and to extend over larger elevational ranges than non-native tropical species. All non-native tropical species were distributed patchily among sites ≤500 m and occupied small elevational ranges, whereas species introduced from temperate regions occupied wide elevational ranges and formed a distinct fauna spanning elevations 500–2000 m. Most native land snail species and ecosystems occur >500 m in areas dominated by temperate non-native snail and slug species. Therefore, knowing the native latitudinal region of a non-native species is important for conservation of tropical island ecosystems because it can be translated into potential elevational range if those species are introduced. Because temperate species will survive in tropical locales particularly at high elevation, on many tropical islands the last refuges of the native species, preventing introduction of temperate species should be a conservation priority.     

Chromosomal sequences and interisland colonizations in hawaiian Drosophila

Of 103 picture-winged Drosophila species endemic to the high Hawaiian islands, all but three are endemic to single islands or island complexes. They are presumed to have evolved in situ on each island. The banding pattern sequences of the five major polytene chromosomes of these species have been mapped to a single set of Standard sequences. Sequential variation among these chromosomes is due to 213 paracentric inversions. An atlas of their break points is provided. Geographical, morphological and behavioral data may be used to supplement the cytological information in tracing ancestry. Starting at the newer end of the archipelago, the 26 species of the Island of Hawaii (less than 700,000 years old) are inferred to have been derived from 19 founders, 15 from the Maui complex, three from Oahu and one from Kauai. The existence of 40 Maui complex species is explicable as resulting from 12 founders, ten from Oahu and two from Kauai. The 29 Oahu species can be explained by 12 founder events, five from Kauai and seven from Maui complex (summary in Figure 5). Although the ancestry of two Kauai species can be traced to newer islands, the ten remaining ones on this island (age about 5.6 million years) are apparently ancient elements in the fauna, relating ultimately to Palearctic continental sources.     

Factors shaping the range-size frequency distribution of the endemic fish fauna of the Tropical Eastern Pacific

Aim To assess the effect of habitat fragmentation and isolation in determining the range‐size frequency distribution (RFD) of the shorefish fauna endemic to a discrete biogeographical region. Location The Tropical Eastern Pacific (TEP). Methods Habitat isolation represents the separation between oceanic islands and the continental shore of the TEP and habitat fragmentation the degree of spatial continuity of habitats (i.e. reefs, soft bottom, nearshore waters) along the continental coast of the TEP. The effects of habitat isolation and fragmentation were quantified by comparing the RFDs of (1) the species found on oceanic islands vs. the continental shore, and (2) species on the continental shore that use different habitat types. Results The RFD of the entire TEP fauna was bimodal, with peaks at both small‐ and large‐range ends of the spectrum. The small‐range peak was due almost entirely to island species and the large‐range peak due mainly to species found in both the continental shore and oceanic islands. RFDs varied among species using different habitats on the continental shore: reef‐fishes had a right‐skewed RFD, soft‐bottom species a flat RFD, and coastal‐pelagic fishes a left‐skewed RFD. Main conclusions Variation in dispersal capabilities associated with habitat isolation and fragmentation in the TEP appears to be the main mechanism contributing to differences among RFD structure, although variation in tolerances arising from the dynamic regional environment may contribute to some patterns. Because diversity patterns are strongly affected by RFD structure, it is now evident that the insular and continental components of a fauna should be treated separately when analysing such patterns. Furthermore, contrasts in RFD structure among species using different habitats demonstrate that a full understanding of the causes of diversity patterns requires analyses of complete regional faunas in relation to regional geography.     

Conservation status of the North American fish fauna in fresh water

The status of the North American fish fauna includes 292 species of fishes in the categories of endangered, vulnerable, rare, indeterminate, and extinct. This constitutes 28% of the known fauna. The status of fishes and their habitats continues to decline, especially in the arid regions of western U.S.A. and northern Mexico. The Endangered Species Act is the most powerful tool currently available to protect rare fishes. While many fishes probably have been saved from extinction by this Act, surprisingly few have improved enough to be removed from under its protection.     

New evidence of ectomycorrhizal fungi in the Hawaiian Islands associated with the endemic host Pisonia sandwicensis (Nyctaginaceae)

Ectomycorrhizal plants and fungi are ubiquitous in mainland forests, but because of dispersal limitations are predicted to be less common on isolated islands. For instance, no native ectomycorrhizal plants or fungi have ever been reported from Hawaii, one of the most remote archipelagos on Earth. Members of the plant tribe Pisonieae are common on many islands, and prior evidence shows that some species associate with ectomycorrhizal fungi. However, until now, the Pisonieae species of Hawaii had yet to be examined for their mycorrhizal status. Here we sampled roots from members of the genus Pisonia growing on the Hawaiian islands of Oahu, Maui and Hawaii. We used molecular and microscopic techniques to categorize trees with respect to their mycorrhizal associations. We report that the Hawaiian endemic Pisonia sandwicensis forms ectomycorrhizas with at least five fungal operational taxonomic units (corresponding closely to species) belonging to four genera. We also report that this tree species is monophyletic with other ectomycorrhizal Pisonia species. We suggest that in light of the newly discovered Hawaiian ectomycorrhizal fungal community and other island ectomycorrhizal communities, dispersal limitations do not prevent the colonization of remote islands by at least some ectomycorrhizal fungi.     

Ocean current variability and the spawning season of Hawaiian reef fishes

Synopsis The spawning patterns of four Hawaiian reef fishes with similar reproductive habits, but different biogeographic distributions were studied from September 1980 to October 1981. Two species are Hawaiian endemics [Centropyge potteri (Pomacanthidae) and Chaetodon multicinctus (Chaetodontidae)] and the other two have pan-tropical Pacific distributions [Ctenochaetus strigosus and Zebrasoma flavescens (Acanthuridae)]. All showed increased spawning activity from January to July, the prevalent pattern among a majority of coastal marine fishes in Hawaii. Environmental correlatives to the period of peak reproduction include cycles of (a) daylight length and temperature which probably function as proximate cues and (b) seasonal variations in ocean current patterns which may ultimately affect survival of larvae and dispersal. Peak reproduction takes place during months when (1) mesoscale eddies most likely occur, and (2) the probability is greatest of drifting objects remaining near the islands.     

Life-history characteristics of eleotrid fishes of the western hemisphere, and perils of life in a vanishing environment

The term amphidromous was coined (Myers in Copeia 1949:89–97, 1949b) to describe diadromous life histories that include migrations, not associated with reproduction, that are between fresh and marine waters. This concept has facilitated evaluations of life cycles among a number of groups of fishes including some belonging to the family Eleotridae. Information was gathered on life history patterns of eleotrid fish species that have been recorded from both fresh and brackish or marine waters of the east and west coasts of North, Middle, and South America, including adjacent islands, seeking evidence of diadromy and especially of amphidromy. Convincing evidence was found of diadromy in the life cycles of four species from the east coast (with another two species possibly in this category), and of three species from the west coast of the Americas and adjacent islands. However, there was convincing evidence of amphidromy in only one species from the east coast and adjacent islands, with another three species or species populations possibly in this category, and in three species from the west coast and adjacent islands. It seems possible from the available information that there may be variation among populations in life cycles of some of these species. However, it remains for the use of modern techniques to allow more definitive determinations of life history patterns of these eleotrid species populations. Serious concern exists with respect to the conservation of all diadromous species because of the worldwide emphasis on river manipulations, especially of dam construction. Resident diadromous organisms are being impeded in their migrations, and thus imperiled in their potential for survival, depending on the nature of river alterations and the abilities of the organisms to cope with them.     

Benthic Community Structure and Invertebrate Drift in a Pacific Island Stream,Kosrae, Micronesia1

Tropical Pacific island streams have poorly understood communities that deserve scientific attention. We examined benthic macroinvertebrates and fishes of the Inem River on Kosrae, Federated States of Micronesia. Larval chironomids, lepidopterans, odonates, and freshwater shrimps dominated the benthos and drift. Diel periodicity in drift was not evident. Nine fishes, two shrimps, and one snail species were identified. Kosrae's stream fauna appears even more depauperate than other Pacific high islands, possible due to its extreme isolation.     

Helminthic fauna of commercial fishes from the Saya-de-Malya bank (Indian Ocean)

The data on infestation of 8 species of commercial fishes from Saya-de-Malya bank (the Indian Ocean) are presented. 43 helminth species were identified: 10 Monogenea species, 18 trematode, 7 cestode and 8 nematode species. The mature worms are observed to be related to a certain host, whereas the nematode and cestode larvae have wide specificity. High infestation degree by Anisakis larvae is found in fishes, especially in Carangidae. At the bank area fishes are found to be free from Acanthocephala while those Acanthocephala are found in fishes from other areas of the Indian Ocean which may be attributed to the specific diet at the Saya-de-Malya bank. On the whole the helminth fauna of fishes examined at the Saya-de-Malya bank does not demonstrate the endemic pattern. The most specific helminth species were found in some fish species.     

Perforated trapezoidal artificial reefs can augment the benefits of restoration of an island and its marine ecosystem

The Gulf of Mannar (GoM) is located along the southeast coast of India. It has a chain of 21 low‐lying uninhabited islands extending from Rameswaram to Tuticorin. These islands are endowed with coral reefs, beds of seagrasses, and other associated marine life. Growing human population has led to accelerated coral mining and destructive fishing practices and this has brought about changes in the bio‐geomorphology of the islands, altered the hydrodynamic conditions, and resulted in severe erosion of the islands. The area of Vaan Island had decreased from 20.8 ha in 1969 to 2.33 ha in 2015. While hard measures have proven successful in preventing erosion, ecosystem‐based measures taking into account the resilience of the flora and fauna yield greater and more natural benefits. A total of 10,600 perforated trapezoidal artificial reef (AR) modules were deployed in clusters along two rows on the windward side of Vaan Island. ARs of 1 and 2 m height were placed respectively along contours of 2 and 3 m depth. The shape and arrangement of the ARs dissipated wave energy through the shoaling effect. As a result, a spit appeared and the area increased to 3.15 ha. The ARs also support epibenthic communities, benthic macrofauna, corals, and fishes. The deployment of an ecosystem‐based multipurpose perforated trapezoidal AR model has been successful not only in restoring the sinking island but also in enhancing the species richness, and it can be adopted as a tool in the restoration of islands and their marine ecosystems.     

Helminth parasites of Madeiran rockpool fishes,with a redescription of Schikhobalotrema longivesiculatum Orecchia & Paggi, 1975 (Digenea: Haplosplanchnidae), and some comments on their zoogeographical relationships

Seven species of Madeiran rockpool fishes were examined for their helminth parasites. Only two of these harboured helminth parasites. The most frequently encountered parasite was the digenean Schikhobalotrema longivesiculatum Orecchia & Paggi, 1975 from Parablennius parvicornis; this species is redescribed and discussed. The paucity of the parasite fauna of Madeiran rockpool fishes and the zoogeographical relationships of the digenean fauna of Madeiran marine fishes are commented upon.