Shell Middens and Coastal Prehistory

Shell middens, the residues of shellfish gathering, consumption, and disposal in the past, have attracted the attention of archaeologists for more than one hundred and fifty years. Although there has been a tendency to view these sites as simply waste heaps, it is increasingly clear that this is usually not the case and that, sometimes, spatially meaningful arrangements of domestic debris of all kinds (fireplaces, artifacts, cooking and sleeping areas) are recognizable if excavations are sensitive enough. Some issues are as relevant and as intransigent as they have been from the beginning: Are they really food waste or could they be natural shell accumulations? Were people living at these sites or are they simply large piles of waste resulting from shell processing? In what ways and how fast did the middens accumulate? How are shell middens related to other archaeological sites inland, contemporary but without shell food waste? Because shell middens are found on all continents except Antarctica and throughout the Holocene time period (the last twelve thousand years), the literature on their excavation and interpretation is enormous and illustrates that archaeologists worldwide engage similarly with counting, measuring, weighing the shellfish, and associated faunal and artifactual remains from these sites. Often, the research involves developing proxies for the kinds of invisible but interesting aspects of the lives of the shellfish gatherers, such as: How many people lived here? How long did people stay at this site? Why did they come when they did and leave when they did? Where else did people live? While Holocene shell middens are ubiquitous, it is also clear that Pleistocene shell middens, while fairly widespread, are found more commonly in coastal areas where early modern humans have dispersed early in their migrations across the globe. It is likely that these traces, in Africa, in Europe, in island South-East Asia and Australia, and along the shores of western North America mark the routes whereby our earliest modern human ancestors peopled the world.

Picking a way forward: valuing and managing traditional shellfish gathering for Littorina littorea

Littorina littorea (periwinkles) have been harvested by hand picking from the shore since prehistoric times. Harvests are generally unregulated, catches are not linked to particular shores and fisheries statistics are considered to be unreliable. The absence of key data has made it difficult to develop harvesting recommendations. Surveys around Strangford Lough, Northern Ireland were used to investigate the size structure and relationships among densities in different size classes. Three size classes were identified in surveyed L. littorea, with mean shell lengths of 0.81, 1.56 and 2.48 cm. Assuming that the age classes represent year classes, data across different shores suggested that the ratio between densities in successive year classes was not constant. Proportionally fewer individuals were found in the larger, older, size class as the density of the smaller size class on a shore increased. This density-dependent relationship was modelled with a Ricker curve for the year 1 to year 2 and the year 2 to year 3 transitions. The predicted transition rates from Ricker curves were used in a size-structured model to describe L. littorea dynamics. An emergent property of the size-structured model is a decline in mean shell length with overall density of a population. This prediction was supported by the survey data from Strangford Lough and by an independent survey of Irish shores. The size-structured model predicts potential harvests of individuals above 2.06 cm as a function of recruitment rate. Maximum harvest was predicted for a density of 5 year 1 individuals m−2, leading to 13.8 year 3 individuals m−2 or an estimated annual harvest weight of 67 g m−2. Modelled estimates of production provide a means to value shores and develop harvest predictions for management purposes.

Inventarisasi Bio-Ekologi Terumbu Karang Di Pulau Panjang, Kabupaten Jepara, Jawa Tengah

The inventarization of coral bioecology is highly needed to identify the real condition of the observed coral, as a database in ecosystem management, as well as an attempt to rehabilitate critical coastal area. Coral condition valuation is conducted by counting the percentage of live coral coverage, by using the Line Intercept Transect method. This research shows that coral condition in Panjang Island falls into moderate category (with 29-49% of live coral coverage), which represent up to 57% from total observed area. Coral that falls under "bad" category (live coral coverage below 20%) is 29%, and only 7% of the observed area can be categorised as good (more than 50% coverage) and "very bad" (less than 5% of coverage). This condition is primarily caused by the decline of water ecology quality caused by sedimentation, west season wave activity, along with human activities like tourism, swimming, fishing, or shellfish gathering. These contributes many instances of coral-breaking caused by gleening. Keywords : Coral Reef, LIT Methods, Panjang Island, Jepara Inventarisasi bio-ekogi terumbu karang sangatlah diperlukan guna mengetahui kondisi nyata terumbu karang yang dilakukan pemantauan, sebagai basis data dalam pengelolaan ekosistem serta upaya rehabilitasi kawasan kritis pesisi. Penilaian kondisi terumbu karang dilakukan dengan perhitungan persentase penutupan karang hidup menggunakan metode LIT (Line Intercept Transect). Hasil penelitian menunjukan bahwa Kondisi terumbu karang di Pulau Panjang termasuk dalam kategori sedang (dengan persen tutupan karang hidup 29 – 49 %) mencapai 57 % dari keseluruhan area pengamatan. Selanjutnya kondisi terumbu karang dengan kategori buruk (persen tutupan karang hidup 20 %) mencapai 29 % dan hanya 7 % dalam kategori baik (50%) dan buruk sekali (persen tutupan karang hidup 5 %). Kondisi tutupan terumbu karang yang relative buruk diduga diakibatkan oleh menurunnya kualitas ekologi perairan yang diakibatkan oleh sedimentasi, aktivitas gelombang musim barat,serta aktivitas manusia seperti wisata, berenang, memancing ataupun pencari kerang turut serta memicu banyaknya pecahan karang akibat terinjak – injak (gleening). Kata Kunci : Terumbu Karang, Metode LIT, Pulau Panjang, Jepara

Effect of trampling and digging from shellfishing on Zostera noltei (Zosteraceae) intertidal seagrass beds

Seagrass beds are among the most valuable ecosystems in the world but they are also among the ones most affected by human activities, and they have decreased significantly in recent decades. In many areas, such as in the Basque Country (northern Spain), seagrass beds occupy areas that are also of interest for human activities such as recreation and shellfishing. They may therefore face a number of pressures that cause damage or irreversible states. Taking into account the limited distribution of seagrass beds in the Basque Country and the interest in their conservation, an eight-month field experiment focusing on the Zostera noltei growing season was carried out to evaluate the effect of shellfish gathering. We used generalized linear models to assess different intensities of trampling and digging, as the most important pressures of shellfishing applied to Zostera noltei beds. The results indicated that shoot density of Z. noltei was negatively altered by trampling treatments and positively affected (as a recovery) by digging treatments. This finding suggests that shellfishing adversely affects seagrass abundance and is potentially responsible for its low density in the Oka estuary. Our findings are important for management and should be taken into account in seagrass conservation and restoration programmes.