Browsing by Author "Machado, Inês"
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- Morphometric relationships, relative growth and roe yield of the sea urchin (Paracentrotus lividus) from the Portuguese coastPublication . Nicolau, Lídia; Vasconcelos, Paulo; Machado, Inês; Pereira, Fábio; Moura, Paula; Carvalho, André N.; Gaspar, MiguelSea urchin (Paracentrotus lividus) populations from the northwestern (Carreco) and southwestern (Aljezur) coasts of Portugal were surveyed to analyse and compare their morphometric relationships, relative growth (isometry vs. allometry) and roe yield. Specimens were hand-collected from intertidal rock pools and sampled monthly during two consecutive years (November 2010-November 2012). Overall, 1220 P. lividus larger than 40 mm in test diameter (542 from Carreco and 678 from Aljezur) were analysed during the study period. Morphometric relationships established between specimen size (test diameter, height and volume) and weight (total and gonad weight) were statistically significant and displayed high correlation coefficients (r = 0.484 - 0.974), with allometric coefficients ranging from b = 0.962 to 1.239 (linear variables) and from b = 2.541 to 3.437 (linear and ponderal variables). Sea urchins mean roe yield was significantly higher in Carreco (7.5 +/- 3.1%) than in Aljezur (6.8 +/- 3.5%) and varied depending on the sampling month. The present data on morphometric relationships, relative growth and roe yield was duly compared with previous studies available on these topics, through an exhaustive review covering the distributional range of P. lividus along the Atlantic Ocean and Mediterranean Sea.
- Spatial patterns of demersal communities from bottom trawl on the Portuguese North Coast (continental shelf)Publication . Felício, Mónica; Gonçalves, Marta; Machado, Inês; Gaspar, MiguelUnderstanding the diversity and community composition of marine communities in coastal areas is of utmost importance to understand how overlapping anthropogenic pressures impact the marine environment. The demersal and epibenthic communities of the Portuguese northern continental shelf were surveyed using a bottom trawl to understand their taxonomic composition, abundance, spatial distribution, and their relationship with environmental variables such as sediment, organic matter, depth and latitude. Bottom sediments were homogenous, being mainly composed by sand particles. The diversity of the study area was low, but high abundance of important commercial species, as Trisopterus luscus, Trachurus trachurus, Palaemon serratus and Merluccius merluccius, in the juvenile stage of life, points out the importance of the area as nursery grounds. Four assemblages were identified, with a visible geographical pattern. Results obtained supply background information that may contribute to the development of future management and monitoring plans for this important and sensible coastal area.