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Utilization patterns of surfzone inhabiting fish.

29

Paranaguá Bay Estuarine Complex

Pontal do Sul

1

2

3

Figure 1. Map showing the studied area in Pontal do Sul, Brazil (

1-3).

Salinity Scale – PSS), wave height (m) and period (s) were measured monthly, as no differences between successive hauls were observed. Wave height was taken with a 2 m ruler as the metric difference between crest and sea level of the largest waves breaking on the surf zone. Wave period was measured from the duration (in seconds) of 11 successive breaking waves and divided by 10 to calculate the period of a single wave. This procedure was repeated twice to obtain an average.

Data analyses

Fish collected from all seine hauls were pooled to provide monthly means, since the same dominant species have occurred and were abundant in the three studied areas. Homogeneity and normality of abiotic and biotic monthly means were tested using Bartlett Chi-square and Kolmogorov- Smirnov tests, respectively (Sokal & Rohlf 1995). To meet the assumptions of ANOVA, number of individuals and biomass were log-transformed while richness was square-root transformed. One-way ANOVA was used to test differences amongst monthly means for the biotic and abiotic data. Monthly averages of standard length were tested with ANOVA to verify the existence of differential utilization patterns of the surf zone habitat by the most abundant species. Moreover, monthly relative

frequencies of gonadal maturation stages, according Vazzoler (1981) scale, were used to assess the false

herring

Harengula

clupeola

(Cuvier

1829)

reproductive activity in situ.

For

operational

purposes,

some

abbreviations were adopted to distinguish between two different species: Mugil sp.1 is one species of Mugil genus that can not be identified since scales were absent on the analyzed individuals; Mugil sp. 2 is the code to mullet Mugil gaimardianus Desmarest 1831, species that no longer exists (Menezes et al. 2003) and S. brasiliensis 1 is the Brazilian sardine Sardinella brasiliensis (Steindachner 1879) to distinguish it from the abbreviation of the serra spanish mackerel Scomberomorus brasiliensis Collette, Russo & Zavala-Camin 1978 (ICZN 2000).

Results Environmental parameters

Amongst the environmental parameters, only temperature differed significantly, mainly in the comparisons between winter and summer months, which varied from 19 °C in June to 28 °C in January. Salinity ranged from 25 (January) to 36 (July); the shortest wave height was 5 cm (June and September) while the highest was 70 cm (May), and the wave period varied from 4.2 s (October) to 11.5 s (April) (Fig. 2).

Pan-American Journal of Aquatic Sciences (2007), 2 (1): 27-39

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