Abstract: The conservation of long-lived species requires extensive, in-depth knowledge of their population structure and vital rates. In this paper we examine the structure of the Mediterranean fin whale (Balaenoptera physalus) population based on the available mortality figures from European stranding network databases compiled over the past 22 years. Such data has enabled us to lay out a first life-history (mortality) table of the population using a simple age-structured demographic model with three life-tables: calf, immature and mature. Our results reveal a high mortality rate in the first stage of life (77% per year), which decreases during the immature stage and falls further during the mature adult stage. In addition, we have calculated the corresponding life expectancies at birth (e0), at entry in the immature stage (e1) and at maturity (e2) under different hypotheses on survival at the maximum age of 90 years (s90) ranging between 0.1 and 3% of newborns still alive. The life expectancy at birth (e0) at the lower bound of the chosen range (s90 = 0.001) is about 6 years, entry in the immature stage (e1) is 8.2 years, and entry in the mature stage (e2) is about 15.6 years. This large increase is the consequence of the higher mortality in the first two stages compared with the mature one. The life expectancies are 10.1, 14.3, and 37.8 years for s90 at the upper bound of the chosen range (s90 = 0.03). The resulting population intrinsic growth rates (r) ranged between −1.3. and +1.7 per year. High juvenile mortality patterns imply that the stationary reproductive value (the number of female offspring produced by each female after a given age x) at the start of maturity reaches a value about seven times higher than at birth. Only optimistically high survival patterns of older individuals would allow positive intrinsic growth rates, thereby enhancing the chances of the population survival.
Abstract: Large-scale monitoring programs are fundamental for the management of overexploited or endangered species. When resources are limited, volunteer data collection could be alternative for researchers needing large amount of data covering a wide geographic extension. Corallium rubrum is endemic to the
Mediterranean Sea. Some coastal populations have been deeply studied although there is still lack of knowledge about the distribution or even its presence along Italian coasts. The present work represents cooperation between University of Pisa and SSI-Italy. Recreational scuba divers have been involved in a monitoring project which aims to acquire data on Italian red coral shallow-water populations and rise the awareness on such an emblematic and patrimonial species. During summer 2008 a questionnaire was distributed to recreational divers. The 616 questionnaires analyzed, covering more than 1600 km of coasts and 390 h of diving, showed an awareness of recreational divers towards red coral: 80% planned their dive aiming to find red coral and 4% reported colony damage. The same methodology applied in other countries could provide useful and comparable data on this precious marine species.
Abstract: Larval settlement of the high value red coral, Corallium rubrum, was studied on three different CaCO3 substrata, viz.
lithogenic (marble), electro-accreted calcium carbonate in the presence and in the absence of cathodic polarisation.
The last two substrata consisted of stainless steel plates galvanically coupled with Zn anodes. The electrochemical
characterization of the settlement device was studied in order to investigate correlations between cathodic
parameters (polarisation potential, current density, calcareous deposit composition) and larval settlement. The
results obtained in the natural habitat (at 35 m depth) showed that settlement was five times lower on the electroaccreted
aragonite in the presence of low cathodic current densities (i 1 mA cm72) compared to both marble tiles
and electro-accreted aragonite in the absence of polarisation. These last two substrata showed similar settlement
values. The implications of these findings on restoration strategies for C. rubrum are discussed.
Abstract: Precious corals have been commercially exploited for many centuries all over the world.
Their skeletons have been used as amulets or jewellery since antiquity and are one of the most
valuable living marine resources. Precious coral fisheries are generally characterized by the ‘boomand-
bust’ principle, quickly depleting a discovered stock and then moving on to the next one. Most
known stocks are overexploited today, and populations are in decline. The unsustainable nature of
most fisheries is clearly revealed by analyzing all available data. Precious corals belong to the functional
group of deep corals and are important structure-forming organisms, so called ecosystem
engineers, that provide shelter for other organisms, increasing biodiversity. Yet, their management
is usually focused on single species rather than a holistic habitat management approach. This review
compares the biology of precious corals as well as the historical ecology and the socioeconomy of
their fisheries to improve precious coral management and conservation. The analysis demonstrates
that a paradigm shift is necessary in precious coral exploitation, not only to conserve habitats of high
biodiversity but also to achieve sustainable fisheries and stabilize a specialized jewellery industry.
Abstract: Gorgonian corals are long-lived, slow-growing marine species dominating Mediterranean rocky bottoms.
Endowed with complex morphologies they give a structure to the whole community, moreover, being effi-
cient suspension feeders, they play a key role in plankton-benthos energy flowand CO2 storage. Thus, the
structure and the development of benthic, hard bottom communities are linked to gorgonian survival. The
red coral Corallium rubrum (L. 1758) is a precious gorgonian endemic to the Mediterranean Sea. Harvested
and traded world-wide since ancient times red coral is a clear example of overexploited marine resource.
This species is structured into self-seeding, genetically differentiated populations, some of which, living
in the shallower part of the species bathymetric distribution,was recently affected by anomalous mortality
events linked to global climate change. The co-occurrence of overharvesting and mass mortality could
dramatically affect such populations. Demographic population models, widely applied by conservation
biologists to check population viability and to project population trends over time are fundamental to
foster survival of such populations matching harvesting to population growth rates. Therefore we set
out a dynamic model of a genetically differentiated red coral population living in shallow waters. This
population is characterised by small/young, crowded colonies and high recruitment rate. On the basis of
the size–age structure determined for this population, a static life-history table, in which survival and
reproduction coefficients of the different size–age classes were reported, has been set out. Demographic
datawere included in a non-linear, discrete, age-structured dynamic model, based on a Leslie-Lewis transition
matrix. Our field data indicate that the recruits-to-larvae ratio is actually density-dependent. Such
dependence, positive for low and negative for high density values, was included into the model and the
effect of colonies of different size–age classes on recruits-to-larvae ratio was considered to be proportional
to the number of polyps they have. We applied such model to simulate the trends of the studied
population under different increases of survival and life-span. As some populations of gorgonians actually
show the dominance of sparse, big/old colonies and low recruitment rate, while others are characterised
by crowded, small/young colonies and high recruitment rate, we simulated the shift from the former
to the latter structure increasing survival and life-span. Our results suggest that a dramatic mortality
increase of bigger–older colonies (due, in the case of red coral to overfishing) could have determined the
population structure we found.
