Supervised pattern recognition in food analysis.

Book reviewFishes of the North-eastern Atlantic and the Mediterranean: Volume II. P.J.P. Whitehead, M.-L. Bauchot, J.-C. Hureau, J. Nielsen, E. Tortonese (Editors). UNESCO Press, Paris, 1986, pp. 510–1007, FF 250, Dfl 105.00, ISBN 92-3-002308-6

Aim South-eastern Australia is a climate change hotspot with well-documented recent changes in its physical marine environment. The impact on and temporal responses of the biota to change are less well understood, but appear to be due to influences of climate,as well as the non-climate related past and continuing human impacts. We attempt to resolve the agents of change by examining major temporal and distributional shifts in the fish fauna and making a tentative attribution of causal factors. Location Temperate seas of south-eastern Australia. Methods Mixed data sources synthesized from published accounts, scientific surveys, spearfishing and angling competitions, commercial catches and underwater photographic records, from the ‘late 1800s’ to the ‘present’, were examined to determine shifts in coastal fish distributions. Results Forty-five species,representing 27 families (about 30% of the inshore fish families occurring in the region), exhibited major distributional shifts thought to be climate related. These are distributed across the following categories: species previously rare or unlisted (12), with expanded ranges (23) and/or abundance increases (30), expanded populations in south-eastern Tasmania (16) and extralimital vagrants (4).Another 9 species, representing 7 families, experienced longerterm changes (since the 1800s) probably due to anthropogenic factors, such as habitat alteration and fishing pressure: species now extinct locally (3), recovering (3), threatened (2) or with remnant populations (1). One species is a temporary resident periodically recruited from New Zealand. Of fishes exhibiting an obvious poleward movement, most are reef dwellers from three Australian biogeographic categories: widespread southern, western warm temperate (Flindersian) or eastern warm temperate (Peronian) species. Main conclusions Some of the region’s largest predatory reef fishes have become extinct in Tasmanian seas since the‘late 1800s’,most likely as a result of poorfishing practices. In more recent times, there have been major changes in the distribution patterns of Tasmanian fishes that correspond to dramatic warming observed in the local marine environment.

Long-term shifts in abundance and distribution of a temperate fish fauna: a response to climate change and fishing practices

Oogenesis in fishes follows a universal plan; yet, due to differences in the synchrony and rate of egg development, spawning frequency varies from daily to once in a lifetime. Some species spawn and feed in separate areas, during different seasons, by storing energy and drawing on it later for reproduction (i.e. capital breeding). Other species spawn using energy acquired locally, throughout a prolonged spawning season, allocating energy directly to reproduction (i.e. income breeding). Capital breeders tend to ovulate all at once and are more likely to be distributed at boreal latitudes. Income breeding allows small fish to overcome allometric constraints on egg production. Income breeders can recover more quickly when good-feeding conditions are re-established, which is a benefit to adults regarding bet-hedging spawning strategies. Many species exhibit mixed capital- and income-breeding patterns. An individual's position along this capital–income continuum may shift with ontogeny or in relation to environmental conditions, so breeding patterns are a conditional reproductive strategy. Poor-feeding environments can lead to delayed maturation, skipped spawning, fewer spawning events per season or fewer eggs produced per event. In a few cases, variations in feeding environments appear to affect recruitment variability. These flexible processes of energy acquisition and allocation allow females to prioritize their own condition over their propagules' condition at any given spawning opportunity, thereby investing energy cautiously to maximize lifetime reproductive value. These findings have implications for temporal and spatial sampling designs, for measurement and interpretation of fecundity, and for interpreting fishery and ecosystem assessments.

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Energy acquisition and allocation to egg production in relation to fish reproductive strategies

The relationship between morphometrics and phylogenetic analysis has long been controversial. Here we propose an approach that is based on mapping morphometric traits onto phylogenies derived from other data and thus avoids the pitfalls encountered by previous studies. This method treats shape as a single, multidimensional character. We propose a test for the presence of a phylogenetic signal in morphometric data, which simulates the null hypothesis of the complete absence of phylogenetic structure by permutation of the shape data among the terminal taxa. We also propose 2 measures of the fit of morphometric data to the phylogeny that are direct extensions of the consistency index and retention index used in traditional cladistics. We apply these methods to a small study of the evolution of wing shape in the Drosophila melanogaster subgroup, for which a very strongly supported phylogeny is available. This case study reveals a significant phylogenetic signal and a relatively low degree of homoplasy. Despite the low homoplasy, the shortest tree computed from landmark data on wing shape is inconsistent with the well-supported phylogenetic tree from molecular data, underscoring that morphometric data may not provide reliable information for inferring phylogeny.

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Testing and Quantifying Phylogenetic Signals and Homoplasy in Morphometric Data

Weight–length relationships of littoral to lower slope fishes from the western Mediterranean

Spear fishing in the Balearic Islands (west central Mediterranean): species affected and catch evolution during the period 1975–2001

Reproductive biology of the brown meagre, Sciaena umbra , is described based on 171 specimens caught by trammel nets and spear gun from April 1998 to October 2000. Histological examination and gonadosomatic index suggest that the spawning season of the brown meagre in Balearic waters is from May to August and peaks in May and June. Seven stages of gonadal development were identified: immature, early developing, late developing, running, spent, recovering and resting. The frequency distribution of oocyte diameter reveals that brown meagre is an iteroparous, gonochoristic, seasonal multiple-spawning fish with aynchronous oocyte development. Size at first maturity was 25.4 cm of total length for males and 29.9 cm for females. Sex ratio varied with fish size, with a tendency for greater numbers of females in higher size classes. Weight-length relationships for both sexes, as well as for the total population, were significantly allometric positive. An analysis of the monthly variations of hepatosomatic index (HSI), and Le Cren’s condition factor showed that HSI is not a good indicator of the lipid reserves of S. umbra . According to our results, current management measures for this species should be re-evaluated.

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Reproductive biology of the vulnerable species Sciaena umbra Linnaeus, 1758 (Pisces: Sciaenidae)

We explore the correlational patterns of diet and phylogeny on the shape of the premaxilla and anterior tooth in sparid fishes (Perciformes: Sparidae) from the western Mediterranean Sea. The premaxilla is less variable, and in spite of the presence of species-specific features, a common structural pattern is easily recognizable in all species (i.e. the ascending and the articular processes are fused in a single branch, as in many percoid fishes). In contrast, tooth shape is more variable, and different structural types can be recognized (e.g. caninelike or incisive). Coupling geometric morphometric and comparative methods we found that the relationship between shape, diet and phylogeny also differs between premaxilla and tooth. Thus, the shape of the premaxilla is significantly correlated with food type, whereas the shape of the teeth is not correlated with diet, and probably reflects the species phylogenetic relationships. Two biological roles, resistance against compressive forces generated in the buccal cavity and the size of the oral gape, would explain the ecomorphological patterns of the premaxilla. The premaxilla and anterior tooth appear to evolve at different rates (mosaic evolution) and represent an example of morphological traits belonging to the same functional unit but following uncoupled evolutionary pathways.

https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1420-9101.2004.00763.x

Marta Linde

Papers

Weight–length relationships of littoral to lower slope fishes from the western Mediterranean

Spear fishing in the Balearic Islands (west central Mediterranean): species affected and catch evolution during the period 1975–2001

Reproductive biology of the vulnerable species Sciaena umbra Linnaeus, 1758 (Pisces: Sciaenidae)

Differential correlates of diet and phylogeny on the shape of the premaxilla and anterior tooth in sparid fishes (Perciformes: Sparidae).

Discriminating between geographical groups of a Mediterranean commercial clam (Chamelea gallina (L.): Veneridae) by shape analysis